


A Purple Mandala

by athirstygoil



Category: Mythtale - Fandom, Undertale (Video Game)
Genre: An au of an au if you will, Bats, Biting, Coercion, Conditioning, Fantasizing, Gags, Helplessness, Hypnosis, Implied Anal, Implied Rimming, Light Bondage, M/M, Masturbation, Mind Games, Mind fuckery, Monsters on the Surface, Multi, Mythtale only a lot later in the timeline, Phantom Sensations, Predator/Prey, Psychological Games, Resistance Play, Sans wears glasses, Sensitive bones, Unsolicited touching, Vaginal Penetration, cadaver mention, dubcon, ectoflesh, forced soul-bondage, forced soul-sharing, gentle enthrallment, hypnotic eyes, implication of death, implied cunnilingus, internal dirty talk, it's still rape if it's unwanted, mental fatigue, mind magic, mind play, neck biting, physical fatigue, secondhand sex, spiral eyes, spirals
Language: English
Status: In-Progress
Published: 2020-05-27
Updated: 2020-09-20
Packaged: 2021-03-02 19:40:34
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 7
Words: 25,935
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24412201
Author URL: https://archiveofourown.org/users/athirstygoil/pseuds/athirstygoil
Summary: Swap!Sans awakens in a maze of forgotten catacombs and accidentally awakens an ancient demon and his eternally faithful servant.
Relationships: PuppyBerry - Relationship, RottenPuppyBerry, Rottenberry - Relationship, SF!Sans/SF!Pap, Swap!Sans/SF!Pap, Swap!Sans/SF!Pap/SF!Sans, Swap!Sans/SF!Sans, Swap!Sans/Swapfell!Papyrus, Swap!Sans/Swapfell!Papyrus/Swapfell!Sans, Swap!Sans/Swapfell!Sans, Swapfell!Sans/Swapfell!Papyrus, Swapfellcest
Comments: 34
Kudos: 54





	1. Chapter 1

**Author's Note:**

> I realize this fic is very self-indulgent and I’m not afraid to say it hints at my personal kinks. If anything it makes for good story material, yeah? :)
> 
> Swap!Sans has a dark blue soul, for integrity instead of a light blue one because he isn’t as patient as UT!Sans.
> 
> Sans uses expressions as well as expletives and he’ll commonly refer to “the Seven Mages” or “The Great White” of the Anti-Void.
> 
> \--
> 
> A small thank-you to my friend oneType! Whose most recent work boosted my motivation to finally finish editing this part and get it posted! You're a treasure, Type!

A whistling like a far away wind jolts Sans as he shakes his head and sits up with a groan. His vision swims. Where…? Holding his skull steady, Sans squeezes his sockets tight, trying to recall what happened. Papyrus wanted Sans to meet him at the park. Something about wanting privacy. But… Sans nearly whacks his head trying to remember. Papyrus also mentioned a surprise. Perhaps because they had spent over a month or two on the Surface? (Sans was still getting used to their calendar system) Maybe for a special secret event like...a birthday? Either way, Sans expected a pleasant one, like a cake, or some trinket he’d cherish (nevermind the cheapness, only the sentiment truly mattered.) Not… _this_.

He can’t be at the park anymore. Not with the dark shapes of his surroundings looming over him with crags rather than low branches, and the ground beneath him a damp rubble instead of grass. The faint sound of dripping water echoes in the stillness as Sans rubs at his temporal processes. It doesn’t make any sense. He’d consider this a rude, elaborate prank if his brother intended this to be the surprise he mentioned.

Knees drawn to his chest, Sans takes stock of himself. Coat, check. Boots, check. Pauldron? Sans pats at the straps buckled along his chest and back, until he solidly feels it on his shoulder. Relieved, Sans brushes dirt off the metal piece fondly. Though he doesn’t explicitly need armor anymore, Sans liked how it added to his signature look, and as it holds significant sentimental value, to lose it would have devastated him. Gloved hands brush past his neckerchief to his skull, and to his dismay, Sans realizes he lost the knit hat he received at a gift exchange. Saddened at this loss, Sans slumps forward. He loves a warm beanie, after all. Overall recovered, Sans slowly stands and scans his surroundings from his seating position. The faintest trace of moonlight shines from above, enough to illuminate how far down he had fallen. Brow ridges furrowing, Sans squints at the rocks above eye level and reaches for a promising handhold.

It breaks apart into pebbles the moment he puts weight on it. 

Undeterred, Sans gives himself a running start and leaps for the next closest one. Grabbing it, Sans swings his weight forward to reach another with his free hand. Scrambling to get a foothold, Sans tests a few nearby rocks. The moment he puts half his weight on one though, it caves beneath him. Slipping, Sans’ eyelights shrink and he covers his skull as he half-rolls, half-slides back to where he started. After the initial shock of his descent, Sans huffs. Brushing pebbles off his visage, Sans reviews his findings. Too steep to safely climb up then...and he doesn’t share his brother’s gift of exploiting the small seams in reality. Rummaging in his coat pocket, Sans fishes out his phone. Low signal. But a signal nonetheless. With bated breath, Sans dials his brother’s number. 

Papyrus answers after the third ring.

“ _bro?!”_ he sounds muffled, his connection laced with static.

“Papyrus?”

“ _what happened—where are ya?”_

“I—” Frowning, he glances at the passage in front of him. Navy eyelights glowing a shade brighter to compensate for the darkness, Sans manages to make out stalactitic projections a few feet from him. “I don’t know, Papy.” Exhaling slowly to calm his nerves, Sans clutches his phone like a lifeline. “It looks like...I’m in a cave?”

“ _stay right there,”_ Papyrus orders, “ _‘m gonna try and find ya—”_

“Papy, wait—!” The call cuts off, and Sans jerks it down in time to see his phone shut down. “No!” he despairs, “this can’t be happening—” Leaning against a sturdier cave wall, Sans covers his teeth with his palm. Sighing, Sans pockets his phone and scratches nervously at his coronal suture. His best course of action right now is to wait. Unfortunately for Papyrus, Sans is not the patient sort. Sans taps awkwardly at the ground with his boot, and without a means to distract him, his thoughts wander. 

Why did he leave home without his glasses? The notion astounds him, especially since his vision worsened under low light. Sans expels an annoyed huff at this inconvenience, along with great many mistakes in addition to it. Mistake number one: expecting to meet Papyrus in a well-lit area. Mistake number two: thinking little of their meeting’s duration. Mistake three: not asking for directions when he clearly needed them. By the Stars, you’d think a sensible monster like Sans would put aside his pride to confirm their exact meeting point. In the middle of a park. At night. Far from home.

...you’d think.

Either way, he still has to adjust to seeing in the dark again without his glasses. And Sans isn’t getting anywhere by just complaining.

...If monsters could create a type of magical means to correct vision, how would it stick to his eyelights? They gave no physical anchor to place normal contacts, and either glasses or goggles made less aesthetically pleasing but practical enhancers. 

Sans begins pacing, grumbling of how monster tech could grow rapidly if the Humans allowed them to establish better monster-centric schooling. They have so much potential, all of them, but it would take time to truly make a dent in that particular field. Especially since Humans lost touch with their magic. Sans notes the echo of droplets from the ceiling, and continues pacing until he wanders away from his moonlit spot. Squinting, Sans feels his surroundings until he finds a texture different from the otherwise stone surface. Tapping it lightly, Sans raps it with a knuckle. Wood.

Further down, he discovers makeshift support beams and reinforcements; iron perhaps, smelling of rust. Has he stumbled across a mine? An underground bunker? Funny though, it didn’t seem like it saw much use for a few decades. Feeling his way down the tunnel, Sans follows the sound of water, now wondering how large this expanse of tunnels has become. The small town near the monster settlement hadn’t advertised any local caves for casual spelunking, nor do they claim to boast any historic mines. Hell, to reach the nearest park means catching a bus to the other side of town. This particular park holds a special place in Sans’ soul, because he and his friends first settled there before relocating to the homes they lived in now. 

More likely than not, Papyrus may have found this secluded place during his numerous escapades and dropped him here as some sick joke. He did something similar, though to a less drastic degree before, when they still lived Underground. But back then, Papyrus tried to protect him in an embarrassingly childish way. Still, he wouldn’t have sounded so worried over the phone if he planned this. If anything, Papyrus would try to scramble to his rescue. Sans chuckles at the thought. Papyrus has his endearing moments, but he also needs to understand Sans can take care of himself.

The wood support beams soon give way to cave walls, and now far from where he fell, Sans peers down the tunnel.

“Hello?” he calls out nervously. His only answer is the faintest sound of dripping water. Sans likes to think he knows his way around unexpected circumstances such as this. The water should eventually lead him to its source, right? (Had he read that in a book or from a forum on the Undernet?) Oh! It could maybe lead to a way out. Listening to the echo of his voice, Sans grits his teeth as he attempts to decipher how deep the cavern would take him. The layout of the Underground he grew up in differed greatly from this place, but if anything, his general knowledge of caves should suffice!

Kneeling, Sans notices the wear on the ground, how smooth it felt in some places. An area of heavy traffic, perhaps? The beams of wood supporting the human, or perhaps monster-made tunnel smell older than he thought, ancient perchance. How preserved though, still remained a mystery. Nervously, Sans carefully hurries down the tunnel. If he knows his caves, he’ll find his way out sooner or later. When his boots splash into a puddle of water, Sans follows it, relieved. Only a matter of time before he finds his way out. But instead of a clearing, he discovers a flooded chamber. 

The water laps at his calves, and stops short of spilling into his boots as he peers into the room. Pillars seemingly carved into the rock wall jut from the far wall. In the middle of the pillars facing him stands a statue on a pedestal. An angel of sorts, or a demon. The wings seem a little off; looking at it from one angle produced feathery tips, while another showed the leather of bat wings. (But, Sans can also blame his blurry vision for that odd observation.) A lengthy shroud conceals their face, and long robes hide their body. One arm reaches for the doorway, while the other pulls back, as if creating leverage to put their whole body into an attack. Their exposed hands flux with a pained expression, as if caught midway through a confrontation, or a struggle. Sans wouldn’t be surprised if under the shroud he uncovers a snarl, frozen in the midst of a terrible betrayal. Their body language clearly shows their displeasure at the moment of the depicted event.

Scrutinizing the statue, Sans cautiously walks into the room. It seems to be the only interesting thing present.

“Whoa...” The pillar bears no name of the subject, yet Sans admires the work. Close enough to observe, Sans observes its beauty. The statue stands well preserved, and breathtakingly detailed, as if carved like those realistic statues he has seen pictures of. Intrigued, Sans reaches a hand out to brush at the veil, as if it would flutter away and reveal the face underneath. He expects it to feel worn smooth at the carved ripples of their robe. Or at least feel of marble like his initial guess. But when his fingers rub almost through it like cloth, Sans blinks in surprise. When he sees the shroud move as if the statue breathed through a hidden mouth, Sans recoils. “What the—” His shrunken eyelights stare directly at where their eyes would be, and Sans catches a glow of purple in the middle of their forehead. Patterned in the shape of an intricate circle, it spins slowly. 

Backing away, Sans summons a bone. For protection. For himself. Staring suspiciously at it, Sans dares to blink. The symbol spins until the shapes inside it push slightly outward—like petals on a blooming flower. When that thought registers, the symbol disappears. Uneased, Sans inches closer, and taps the shroud with the blunt end of his summoned construct. The veil lay still, like a rock should. Brow ridge furrowed, Sans touches the shroud again.

This time he feels the texture of stone.

Cold, unbreathing stone.

Soul beating almost through his chest, Sans positions his weapon between them. Warily, he keeps the statue within visual range as he steadily backs up and runs from the room. 

—

In a corner of the chamber, hidden by the water and shadows, a figure gasps as they scramble from their watery prison. Robes weighed by water, they jerk with wildly bright eyelights to face the statue.

“m’lord...” they rasp, stumbling to aid their master. The figure on the pedestal visibly quivers, outstretched hands frozen in half-clenched agony as their entire being shakes in an effort to maintain their form. Reaching for the hem of their robes, the cloaked monster drags their shaking body forward to hush their lord’s haggard, muffled cries. “ _m’lord!_ ” they croak. With a violent jerk, the winged figure slips from their perch. Claw-like hands clutch the servant’s cloak as the servant catches them mid-fall. At the contact, the draping robes of the winged monster contract between cloth and stone.

“ _Servant_ ,” they falter, speech half present and ethereal as they rip at the cloth covering their neck, “ _hurry—_ ” Fingers sharp as razors scrape the half-stone robes as the servant plunges their gold fangs into their master’s exposed cervical vertebrae. Purple magic dribbles from their partially stone neck as the servant drinks. A sharp hiss resounds as their lord’s magic cuts off midway through feeding, forcing the servant to withdraw. Despite the short duration, the small amount of magic renews a stable coherency to the servant, and their now alert eyelights train on their master’s visage. 

“m’lord—” they breathe, “how?”

“ _Another—_ ” their lord hacks, still fighting the magic binding them in stone, “— _is here._ ” The taller monster holds onto them protectively as their master abruptly spasms between stone and flesh in the servant’s arms.

“m’lord!!” Protecting their lord’s head, the servant waits until they safely manage to retain their physical form long enough to speak.

“ _He needs—_ ” their master gasps between breaths, “— _to break the seal—_ ” Here the servant sees the seal binding their lord in stone flash momentarily. One of the knots of the spell has broken. Like a flower, frozen mid-bloom. Amazed, the servant grips with growing hope at the flowing, half-frozen robes of their master.

“m’lord,” they nearly weep with joy, “what do you require of me?”

“ _Acquire him—_ ” the half-statue of a presence urges, “ _quickly…_ ”

Though the servant knows they haven’t asked permission, they check on the distressed soul of their master. Purple still, but only just. At each passing second, it’s rapidly losing its luster and strength as the residual blue motes of their visitor falls away, leaving behind patches of increasingly growing chasms of black. Reluctant to leave their lord in such a state, the servant bows as they release them. Their master begins stiffening not long after they make their request.

“as you wish, m’lord,” the servant whispers. Their brow furrows from under their hood as they worriedly back away from their master.

Fully stone again, their lord waits imploringly as the calf-deep water lick at their robes. The servant turns away, knowing it will take more than a closer proximity to revive them again.

It will require more than he would willing give.

Lifting their head, gold fangs glisten under an amber light as the cloaked monster sweeps their cape upward and dissolves into bats.


	2. Chapter 2

**Summary for the Chapter:**

> Everything gets just a little worse for Swap!Sans.

**Notes for the Chapter:**

> Thanks for waiting! 
> 
> I started writing this specific fic in 2017 and I've been working on it on and off throughout the years until I literally hit a slump. Save for a few parts and final edits, this fic is basically finished. I'm really glad to finally be posting it though, this story has been dear to my heart and I hope to see it to its end!

Trying to retrace his steps away from the chamber, Sans navigates through the tunnels, listening for any more traces of running water, clean air—anything but another flooded room with weird statues. Gasping, Sans fights to steady his breathing. Gripping his weapon, Sans scans the tunnels, navy eyelights quivering from the encounter. He stumbled upon something he shouldn’t have. Striding quickly through the channel, Sans decides not to wait to find out who or what that was. Splashing through now knee-deep water, Sans follows a tunnel until in vain, discovers a dead end. 

“Damn,” he hisses. Squinting, Sans draws near, and brings his acoustic meatus to one of the larger openings. Waiting, Sans listens until he hears the clear hiss of airflow. Eyelights brightening, he runs a gloved hand over the debris and hooks his fingers into the wide cracks in the rubble. There. Brow ridge furrowing, he takes his summoned femur and snaps it over his knee. Driving the splintered bone into the crevice, Sans adjusts it for proper leverage. 

No point picking a different path when he can create one. 

Summoning the strength to move the infernal boulders, Sans grunts loudly until he feels one shift. Pouring magic into strengthening the femur, Sans expels one last cry and wrests the boulder enough it finally gives way to a large opening. Breathing heavily, Sans laughs aloud in celebration. Climbing over the fallen rock, he peers down the newly opened passage and a stench so vile floods his senses, it nearly knocks Sans off the boulder entirely. Covering his nasal aperture with his neckerchief, Sans coughs.

“By the Seven Mages, that reeks!” A strong scent is but a means of distraction though, and despite the muffled sirens ringing in his skull, despite the insistent thoughts warning him to turn back, Sans gives in to his curiosity. He allows his construct to dematerialize as he sloshes his way forward, a thumb and forefinger pinching his nasal ridge through the thin fabric. Not too far along, the warning bells ring louder in his head as Sans realizes the overwhelming stench surrounding him smells like iron. He only takes one more step forward when he realizes it smells like death. Sans nearly runs into something at his feet. His dark blue eyelights brighten ever so slightly at the large shape just beneath the water. With a shudder, Sans abandons further progression entirely.

Monsters never rot, nor stink of blood.

Monsters never leave bodies.

In fact, what remains has not rotted entirely away.

Despite some exposure to water, whatever lay before him Sans can still identify. The fact he can makes it all the more unnerving.

Hastily backing away, Sans retreats and decides to follow a different path.

\--

The camp of bats divides themselves throughout the passageways in search of this long-awaited disturbance. He won’t get far, not while the servant still has their master. Not while they still have an inkling of hope. Sensing seismic activity along the walls, the swarm locates the intruder, and as the bats gather to reform their main body, the servant watches. It feels as if an eon has passed since they last saw another monster besides their beloved master. As the servant observes him through the few bats they allow ahead, they come to one certain conclusion: the world has changed drastically since their imprisonment. 

This skeleton with his dark blue eyelights and subtle fangs, this monster whose magic awakened their Lord, and in turn, the servant—proves plainer than they originally imagined. Had he not the exposed skull, the servant wouldn’t have guessed this intruder a monster at all. But...to have awakened them… He must house a well of unfathomable power. Despite the invariably pressing matter of convincing him to return with them, the servant reasons the safest option is through observation. What better way to discover the best possible method of persuasion for a being who can likely destroy them if given the chance? (Especially since using force remained the absolute last resort.)

The servant reaches him in time to see the skeleton retreat from a previously closed off tunnel. Sending another bat discreetly ahead, the servant scans the cave wall. Their previously unexpected guests sought shelter here. An honest shame, what happened with them. If only the intruders hadn’t tried to leverage their Lord against them. In the end, after careful observation, the party lacked what the servant sought and had to be removed.

But _this_ visitor, this _skeleton_ is exactly what they need.

Still, the servant has to be certain.

Slowly they dematerialize into the camp of bats and stealthily move closer. The servant treads along the walls and ceiling, piece by piece, bat by bat, until they can practically smell the magic coming off their target. They steal a glimpse of the deep blue of his eyelights, and the servant is so close, so within reach—their still-reforming arm stretches forward, their fingers practically grazing at the bone of the skeleton’s face.

\--

Sans notices the bat as it flies past his peripheral vision, its wing narrowly nicking his zygomatic process. Startled, he nearly trips to avoid it. 

“What the—” Sans reels, interrupted by something leathery between his teeth. “Mffph!”

A soft voice hushes him, and Sans stiffens. As the leathery feel of the thing over his mouth changes into bone, Sans tastes a disgusting mix of rust and stale water on his conjured tongue. Screaming past the hand over his teeth, Sans stamps a foot back and grabs the arms of his assailant. With all his strength, he flings them over his shoulders and downward. Into the water the other person? Monster? falls, but instead of a splash, Sans witnesses the figure explode into a colony of bats. Eyelights shrinking, Sans summons a twin-set of sharpened humeri before backing away. 

First breathing statues, now this?!

Where did they come from?! 

Where can he go?

Eyeing the nearest passages quickly, Sans hightails it out of there, and runs through another tunnel. The swarm swiftly pursues him, their squeaks echoing behind him. Panicked, Sans whacks at the bats with the butt ends of his weapons once a few catch up with him. Some cry out as they slam into the walls of the tunnel. Others shriek at this retaliation. Desperately, he sloshes through the increasingly water-filled floor. 

What do they want from him?

What should he do?!

Would he meet the same fate as those people in the blocked off tunnel?

The sound of water thunder around him as he splashes through the tunnel. The bats in their pursuit begin squeaking in a strangely noisy way. The only other way he’d describe it is vocal. Sans swears at each sound, he hears them disjointedly plead...he stop? Catching fragments of their cries, Sans halts, and realizes the bats? The monster? spoke in multiple voices to _warn_ him _._

_Not._

_That._

_Way!_

Clutching his twin humeri, Sans pauses and faces them. The deafening rush of the falls ring through his skull and his sockets widen as the colony catches up to him. What else can he do now?

“ _enough,”_ a voice echoes disconcertingly over the din. A shiver runs down Sans' spine as he involuntarily stiffens.

By the Great White?!

A face unexpectedly appears in front of Sans, one with glowing, dark bronzed eyelights blinding enough to daze him. Bright with fright, his navy eyelights shrink as Sans witnesses the other monster reach for him like when Sans convinced Alphys to seriously spar him for once. If Sans wasn’t also a monster, the motion would have all been a blur. With the waterfall behind him and his pursuer up front, Sans sees no other escape. The water shifts and laps at his legs as Sans makes the desperate decision to let the current sweep him away. Like a rag doll, he rolls with the waves until it spits him out backward down the falls.

Sans catches a glimpse of amber eyelights as they follow him down, their cloak rippling almost like wings. In horror, Sans watches as they accelerate after him. Falling too fast to escape, he tastes the soaked fabric of their shirt as their sleeve collides with his teeth. The flow of the water rushes loudly past as his cloaked pursuer draws closer. From under their breath, Sans hears the low murmur of speech—almost unintelligible to his acoustic meatus—as the water engulfs them both.

—

In the few moments the water has dragged him below, Sans realizes he doesn’t want to die here. Not in the dark and chilling cold of an unfamiliar cavern—not drowning underground and alone. He wants to die old and happy, aging the gentle way all monsters do when they haven’t yet had offspring. 

Papyrus should have come out sometime before the waterfall to reveal what an incredibly elaborate prank this had truly become. Sans should be chuckling, embarrassed at how easily he had fallen for such a jape—Not searching for a way out of these cavern walls, not fleeing for his life waiting for the brother who may never come. They should be laughing about how Papyrus pranked him good this time, and he’d come to his rescue at the nick of time to tease Sans about the time he shouldn’t have gotten Papyrus a jar of honey that tasted like bootstrap molasses for his birthday. Or to remind Sans of the time he risked his neck to save Sans when Papyrus grossly misjudged the entire situation.

The jokes should have ended hours ago, before the bodies, before the bat explosion—but they didn’t. 

But if the japes never ended, did they ever begin? 

The gravity of the situation hits Sans at the same time one thought occurs to him: he can truly die here. They could catch him and kill him like those people in the blocked off passage. He may never see Papyrus again.

Processing the panic, Sans squelches the descending hopeless thoughts with ones unlike them. No, he won’t allow that. _Not while he retains the self-proclaimed title of the Magnificent Sans!_

Sans’ soul shines bright from under his clothes. 

He will not. Die. Here! 

An untold amount of magic erupts from his being as Sans fights to swim upward. He never prioritized learning how to swim, not when Undyne mustered enough confidence to show him how. Not when Papyrus tried to make it a point that the water from the marsh only slightly differed from the icy waters of Snowdin. Oh how he regrets not learning now.

The water bears down on him heavily, and though Sans does his best, partway through, the raging falls interrupt what progress he makes, and drags him deeper again instead. Choking on the water engulfing his bones, Sans gurgles as the cascade throws him into the dark depths below. He doesn’t want to die this way, but perhaps to die now will count as a blessing to the alternative. His flickering eyelights begin to disappear when an otherworldly presence grasps his entire being. Their cold touch seizes Sans before he can fight his rescuer, and strong, thin arms lift Sans effortlessly from their watery prison. Away from the water, away from the falls. All along, Sans inwardly hopes his brother has saved him.

To prove his faith in Papyrus justifiable.

As he and his rescuer surface, Sans has a chilling thought: if he calls for Papyrus...will _they_ answer instead?

—

Sans coughs as he clutches at the otherwise dry stone beneath him. His zygomatic process drags intimately onto the rock. Distantly, he hears a whoosh as a wind of unseen origin sweeps near. Sputtering, Sans reflexively heaves and gasps, expelling whatever water is left. Vision still blurry from the water in his skull, Sans squints, and almost swears he sees the shadow behind him shake off giant wings before tucking them away. Remembering his situation, Sans’ eyelights shrink as he stiffens.

Quickly scanning his surroundings with his peripherals, Sans curses when he realizes he can’t get a better view to protect himself. They block the way, and the waterfall’s roar makes it difficult to hear— Whirling around, a short vertebral dagger in hand, Sans defends himself from his crouched position. 

“ _Don’t—come. Any. closer!_ ” he warns, eyelights gleaming. His assailant, his rescuer, lifts their open palms to him. It’s here Sans gets a better look at what this monster is; though their aged metacarpals reveal enough. “What do you want with me,” Sans asks carefully, “Who are you!” A gold shimmer cracks into a smile from beneath their hood.

“i am naught but a humble servant,” they answer, stepping unflinchingly forward. Sans immediately lengthens his dagger with magic, the point now as long as a sabre.

“I said—” he reiterates, “—no closer!” The servant’s gold canines gleam as they grin, amused at the gesture. “What do you want?” Sans repeats, slowly standing, “and no funny business.” The servant eyes his weapon before looking down at him, as if deciding what to say. “Talk!” Sans commands. A brief pause, and it almost sounds like their bones rattle from beneath their cloak. “What’s so funny?” Sans demands with a frown.

“all i want is your cooperation,” the servant replies, their grin gentle. Faster than Sans can blink, the servant pushes his sabre away to face him, now inches away— “all _you_ need to do... _is lower your weapon._ ” Those amber eyelights encapsulate his vision once more, but only for an instant. Leaping backward, San covers his sockets with his arm. He thrusts his weapon out, to intimidate. For protection. Waiting on edge, Sans grinds his stance and waits for a blow. But when nothing happens, he briefly peeks over his arm before shielding his eyelights once more.

“Why should I trust you?” Sans hisses. “You attacked me with those bats!”

“their purpose was not to frighten you,” they explain, “but to observe. and when you ran, i sent them after you in fear of this exact situation occurring, or worse.”

“You!!” Sans scoffs with disbelief at the impertinence and gall, “If you hadn’t tried to get me from behind we wouldn’t be down here!”

“a mistake on my part,” they respond calmly, “and as i have remedied my mistake by saving you, i would like to think i have earned the right to be heard.” Peering at them from over his arm, Sans looks them over. The cloaked monster doesn’t seem to have anything up their sleeves, though their bats may have taken shelter amongst the fabric. Unconvinced, but willing to listen, Sans lowers his weapon cautiously.

“Tell me, but make it quick.” The servant’s stance becomes taller almost, as they speak gravely.

“i need you to return with me. i need your help.” Sans scowls doubtfully.

“You should have asked like a normal person instead of chasing after me!” he counters.

“not many would trust a stranger who walks up to them in a dark cave,” the cloaked monster points out. “you are no different,” they refute, “as _you_ attacked _me._ ”

“How was I supposed to react when someone skulking in a dark corner puts a hand over my mouth?” Sans defends. They look at him, almost hurt at the accusation. Annoyed, Sans huffs. “Fine,” he concedes, “ _maybe_ the throw was a little over the top, but it wasn’t unreasonable of me.” 

“of course,” the servant replies, “i had frightened you. i had not meant our introduction to escalate so far.” Sans snorts despite himself.

“Why the heck did you go about it the way you did? I wouldn’t have thrown you if I knew you weren’t a threat!” 

“i suppose in a way, i was...testing the waters. as to go about it a different way would have resulted in a more...uncertain conclusion.” Sans thinks about this briefly.

“Fair enough,” he agrees. “I won’t attack you if you give me no reason to, deal?” Sans catches the glint of gold under their hood.

“for you to see it as i is more than acceptable,” they smile. Sans’ brow ridges knits at the choice in words. Something about them seem...off. “will you return with me willingly?” they inquire, interrupting Sans’ thoughts.

“Where?” Sans asks tiredly. He hadn’t noticed how much energy he used up, running around and lifting heavy boulders. The adrenaline from the plummet off the waterfall must have worn off minutes ago.

“to where my lord awaits me.”

“Your lord?” Sans pinches at his nasal ridge in an attempt to remember anything of significance. “That statue?” he offers.

“yes!” they beam. More than confused now, Sans dispels his construct. He still has his suspicions about this monster, but they haven’t shown any signs of threatening him further. Though this leaves him somewhat vulnerable, now that Sans’ weapon is gone, he can replenish his magic reserves for a later event, considering the low chance of him eating anything any time soon.

“I...I need an explanation,” he requests. “What _are_ you? What is your...master?” Amber eyelights flit between Sans and their surroundings.

“i am what you would call—” the servant cocks their head in thought, “—what do they call us these days? a djinni...a ghoul, a creature of the night—”

“A vampire?” Sans prompts. What other creature can fly, has fangs, and can shapeshift into a colony of bats? Sans backs away. There's an unsettling feeling that hangs over him at this realization. There are also no other place left for him to run, nor are there other waterfalls to jump off of either. “What makes you think I’ll go with you at all?” Jaw askew, the cloaked monster sighs.

“you ask so many questions when you should be asking just one.”

“And what might that be?” _Dear_ **_Stars_ ** Sans needs to _shut up_ and find a way out. **_Now._ **They offer him a wry look.

“as powerful of a monster as you appear, you need all your strength, do you not?”

“For what?” Sans continues asking foolishly. 

_Stop._ **_TALKING and RUN!_ **

“to oppose me of course,” the servant answers, as they casually catch Sans by the chin.

**_Fuck._ **

Readying a punch, Sans’ blue eyelights flare as they lock onto their amber ones. Sans realizes a little too late his fist still shakes just behind his skull instead of punching the fuck out of this monster. It hangs pulled back and ready, yet the power of his swing sticks otherwise fast. Grunting, Sans struggles to move, only to see his core shine a darker shade of blue from under his clothes. His stare lingered longer than he realized, and the servant used it to their advantage. Slowly stepping aside, the servant sighs again, this time in seeming disappointment.

“i had hoped it would not come to this,” the servant shakes their head, “but you leave me no choice.” Frozen in place, Sans’ eyelights flit between him and the servant. “ _relax,”_ they whisper, as the servant touches two distal phalanges to Sans’ glabella. “ _rest now._ ”

It’s like an overwhelming suggestion enters Sans’ skull, overriding him completely. It’s like the only thing important in his world right now is rest.

Sans doesn’t notice when he falls into the servant’s waiting arms.


	3. Chapter 3

**Summary for the Chapter:**

> Sans learns just how dangerous and gentle Slim can be.

**Notes for the Chapter:**

> You know when you can't immediately identify someone because you were focusing so much on something else? That’s why Sans doesn’t see at first Slim’s resemblance to Stretch until this chapter.
> 
> —
> 
> I’m so glad this fic is so well-received!! Thank you so much everyone! ;w;

If Sans doesn’t think he can get more drenched, something icier and colder than the water itself leans against his spine. His teeth bite down on soaked material as Sans jumps in response, now fully awake. His skull nearly collides with a wet wall of rock, but something cushions him from the impact. The roar from the waterfall is replaced by the trickling of droplets as they patter from the ceiling. Panicked, Sans’ eyelights wildly take in his dark surroundings. Where are they—? How long was Sans out?!

_“be at peace,”_ a lulling voice assures him, as a gentle but firm grip twists Sans’ arms behind him. “ _you are doing so well_.” Sans’ soul drops, and he instinctively leans on his side to kick at the unknown presence. They hold solidly against his maneuver, and manage to dodge his boot as Sans screams through the gag. “ _ah ah...”_ the soft voice clicks in disappointment, “ _still yourself now_.” 

A light touch to Sans’ hip, and before Sans can get up to run, his legs fall to the floor like dead weights. Alarmed, Sans’ shrieks are muffled by the wet fabric between his teeth. Navy eyelights glow brightly, smoking with fear and intention. “no, we cannot have that now,” the servant chuckles bemusedly. “there is no need to be afraid,” they shush, tying a heavy fabric around his wrists. The smallest surge of magic Sans built immediately dissipates. Muffled cries escape from his teeth and his captor merely pets his skull familiarly. “you are in good hands. i have not tried to harm you, have i?” 

Why were they tying him up? Why the gag? Weren’t they just talking like normal monsters a few moments ago?!

Hurt by this, Sans focuses all his willpower in one last futile attempt, and manages to push them off with his pauldron-covered shoulder. Sans jerks to face his suppressor as their hood falls away. Steadying their footing from the weak but effective surprise attack, Sans’ glowering eyelights shrink with shock once he catches a good look of their face.

“P—Pyruh?” The tall skeleton blinks. Half-lidded sockets acknowledge Sans, and their gold fangs glimmer in the glow of their subfusc eyelights.

“no,” they gently reply. “i am not.” Drawing near, Not-Papyrus hums as a thin finger ghosts across Sans’ shoulders, making him flinch. It can’t be. Papy has all his teeth, and the distinctly long fractures above their canines make it almost impossible to thoroughly cover up. The one on their left side climbs high on their face, cutting through—no, absolutely exceeding their socket, while the one on their right stops short of their nasal cavity. The fact they look so much alike jars Sans. The fact he has trouble seeing them as some capable kidnapper becomes a dull concern. “for all intents and purposes, you may call me...slim,” they smile, “but i prefer my thralls to refer to me as—” Their face appears mere centimeters away, and Sans smells the scent of old magic and stale air clinging to their cloak. “— _master_.” Jolted from his initial astonishment, Sans musters enough resolve to shove the ghoul away with a headbutt to their nasal bone. Taken aback, they retreat with a quick jerk, phalanges clapped over the aperture.

“’m not your thrall,” he spits through the gag. The act of defiance surprises the servant, and after a moment to recover, they stare with hollow sockets before chuckling pointedly with amusement.

“ah, so you are a real fighter, are you not?” Slim asks, voice slow and strangely soothing. “training all you can, with all your might to become the best of knights?” Gazing down at Sans with eyelights the color of dark honey, they smile like they’re withholding an exciting secret. “reminds me of someone _i_ knew.” The amber glow of Slim’s eyelights close in on Sans. When he realizes his stare lingered, Sans blinks furiously. Their bemused chuckle softly hangs in the air, like soft bells in a serene field, or crickets chirping around a quiet lake. “and you know what it is like, right?” Not-Papyrus adds, “to work so _hard_ , and do so _much_ you need to give yourself time to _breathe._ ” 

Closer this doppelganger of his brother leans. Gradual and warm, like a fire near kindling. Like embers sparking to life. Reminding himself this fellow knocked him out and dragged him here with no easy escape, Sans readies to ram this copy of his brother, to get away from their strange advances— But as Sans summons the strength to push past the magic weighing down his soul, something stops him. 

Something that feels like viscous honey all over his teeth. 

Something that dunks his soul in a sudden chill. 

Something frightening, and primal. 

Sans feels his soul freeze up in his chest.

“and it is during those times,” Slim continues with a sonorous tenor, the faintest of smirks across their teeth, “the best thing a knight needs is _sleep_.” 

When did...when did it become this hard to look at them? Sans squints upward at Slim, like a bright light flashed into his sockets. He’d be rubbing at them if that Stars-damned blue magic wasn’t— Smiling down at Sans’ hazing blue eyelights, Slim reaches for his face. “do you not agree?” Stroking the tears from Sans’ infraorbital foramina, they deftly lower the gag.

Sans stares as defiantly as he can at them, navy eyelights small yet sharp despite how blinding Slim has become.

“I don’t sleep,” Sans utters with as much conviction as he can muster. Not-Papyrus only smiles gently, almost condescendingly, like one would to a child.

“give yourself time,” they assure him, with a slight grit to their teeth. The hand brushing Sans’ face descends down his neck and rests on his clavicle. “you will learn soon enough.”

Sans doesn’t expect the claws when they erupt from Slim’s distal phalanges. He doesn’t register the pain until sharp bone pierces through his coat and shirt, hooking excruciatingly into his clavicle and closing the small distance left between them. As Slim yanks Sans’ face to theirs, Sans can feel their metacarpals dragging against the underside of his clavicle.

Confused and panicked, Sans struggles, bound hands desperate to summon something, anything. They said they wouldn’t hurt him!! They— Sparks of blue magic diminish as they hit the air, and helplessly, Sans stares wide-eyed at his captor.

Their gold fangs gleam as the servant gazes hungrily down at him. Eyelights shining a tarnished gold to match, a growl rumbles through their ribcage. Too stubborn to yield, Sans foolishly maintains eye contact. Now glaring into those eyelights rimmed with gold, Sans notices something...subtle in them. Squinting, he leans involuntarily closer.

Spirals?

At the realization, they seem to bore into him, and Sans shuts his sockets hoping to remedy his mistake. _You idiot!_ He chides himself, _D-don’t look at them!_

His warning too late, the spirals already take effect, and the room spins. Consciously aware he needs to turn his head away, Sans manages to twitch it to the side before the grip on his clavicle distracts him with enough pain to expose his vulnerable eyelights once more. As the comforting amber glow meets him, Sans finds he can barely keep his sockets open. Staring with half-lidded sockets at the glow emanating from the servant’s beautiful eyelights, Sans blearily feels his teeth part and magic pool atop his hyoid bone.

“does that not feel better?” Slim queries, “you must understand then,” they chuckle darkly, despite the playfulness in their eyes. “since you continue to fight, it will only mean falling _further and deeper for me_.” Their amber glow brightens ever so slightly, and blinds Sans once more, but he can’t look away. “ _go on_ ,” Slim insists, “ _resist me. fight me like the hero you aspire to be.”_ They lean close, so close now, and Sans doesn’t realize their nasal ridges almost touch as Slim’s teeth brush his acoustic meatus with a whispered proposition. “ _and i will personally see to your safe return. right where you came from_.” 

Cringing, Sans stiffens as he waits for them to move away. When they finally do, Sans’ head lolls forward with relief. Part of him wants to prove this creature wearing his brother’s face wrong. Another, fears giving in.

But his options are few and far between. What other choice does he have? Even if Papy does manage to find his way into the cave, Sans is nowhere near the spot he said he would be. No, Sans has to rely on himself.

Their phalanges slowly uncurl as Slim releases their hold on Sans’ clavicle in a graceful retreat. Sans still stares up at them as his knees buckle under him. Slim chuckles at this development. “i wish to give you a fighting chance, hero,” they simper. “do your best now,” they sing. “resist me.”

Aware of their offer, Sans grinds his teeth to take up their challenge. As soon as he breaks eye contact, the dizziness returns tenfold, but still Sans tries. He stands slowly, still deciding how to fight them with what little energy he has left. They wait, patiently smiling. Their facetious approach distantly angers Sans, but he can’t find it in him to care.

He takes stock of himself, best he can. The magic holding down his soul disappeared; he can make a run for it. But first he has to get his magic sorted so he can get the fuck out of this cave. He’ll need to loosen the ties that bind him. Slim would let him, too. It would be easy. 

Easier said than done.

No, he has to. He has no other option. They want a fight, so Sans will give it to them. Sans straightens as resolutely as possible and tests the binds on his wrists. The fabric lies taut, and Sans vaguely feels a tug of opposition. He already expected the weight over his soul to be blue magic as he is familiar, but they have also managed to suppress his magic. How? They hadn’t wounded him until they scratched his clavicle. They broke no bones, so how else did they get a hold of his marrow? 

If this is blood magic like Sans suspects, he knows little about it, as well as the misnomer it carries among monsters. But if it isn’t that, it has to be some kind of paralyzing spell— Have they done something before they dragged him out of the water? Has he sealed his own doom without knowing? His thoughts swim and the lightheadedness that follows does little to help.

Focus, he has to— Sans shuts his sockets. He visibly sways as a result. 

Making deals with creatures like Slim means risking a mistake, but what else can he do? They promised if he resists, they will let him go. That means he has to withstand them. Outsmart them, play them at their own game. But how can he do that if he can’t stand properly? Though he made his decision, Sans feels unable to act on it. His body hangs heavily around him with fatigue, judgement clouded by pain and indecision. Slim seems to notice this inner struggle, and mercifully steps forward.

“i will release you myself if doing so grants you a fighting chance,” they murmur, stepping behind him. Sharp claws rip at the cloth binding Sans, and instantly his magic surges back to him. If Sans prepared to feel joy, dizziness overcomes it instead. Hands now freed, Sans clutches at his temporal processes as he falls to his knees again, a whine ringing from his teeth. 

Something's wrong— _something is_ **_wrong!_ **Sans gasps, frantically searching to piece together what was missing just moments before Slim freed him.

“What did you do?” he utters, unable to hide the desperation and panic leaking from his voice, “ _what—_ ” Slim kneels in front of him, and gently cups his face in their hands. 

“ _i only do what you let me_ ,” they assure him. Part of Sans wants to believe them, but he can’t—he _can’t._

“You’re lying! You did something! _What did you do?!_ ” Sobbing, Sans pushes at them, but they hold fast.

“look at you,” Slim continues, maternally stroking his face with their thumbs before settling their hands on his shoulders, “you have come so far. it is only natural you would feel this way. it is only natural you would be afraid.”

“I—I’m scared,” he admits, “But I’m—”

“you need not fear while i am around,” they coo. “i have only done what i did for _you_. to help you understand. to keep you safe.” Sans looks down, unsure. “look at me,” Slim requests, urges. “let me help you.”

His clavicle still aches from where they grabbed Sans, but staring at their amber eyelights seems to rid him of the overall pain. Faintly, Sans finds his head nodding. They helped though, didn’t they? He worries too much. He can trust them to help. They can guide him out, take him back. Keep him safe. That makes sense...

No wait, what happened to resisting this fucker?

Weakly, Sans moves his skull, to get it away from Slim’s firm grip. They seem...almost pleased? As well as... _hurt_ he nearly fell for their ploy. “you are still so hesitant,” they observe. “will you not let me help you?” A sudden surge of magic courses through Sans as he uses what little strength he has to jerk away. Their brow ridges rise, their sockets glower. At the opposition, Sans almost swears he feels their claws poke out again as he stumbles back, limbs still heavy from the aftereffects. He has to fight! He still— His gaze falls on their towering height hidden by their rippling robes, their glowing amber eyelights, and Sans’ courage drains to a trickle. He can’t help but feel he made a dire mistake. As he waits for them to move, Sans has an epiphany. Messing with a monster like them means maintaining a strength he needs to muster, and enough willpower to drag his way out. Both of which, he currently has little of. “it is good to see you try,” they chuckle, “no matter how futile it is. keep going,” they urge. “ _resist me_.”

When Slim lunges forward and latches onto him, Sans fights to kick his weighted limbs, with difficulty. He manages to softly nudge them away with his foot as Slim catches him by the coat. He tries to summon the strength to bash him with the sharp end of his pauldron as Slim slips it from his shoulder.

At each failure, Sans exhaustion becomes more apparent to him, like a part of him _wants_ to give in. It ultimately feels like every harrowing event he experienced stacks up against him, like a voice forcing him to acknowledge his weariness. Like the bats, the voices come out disjointedly, yet simultaneously. They ring throughout his skull in a dizzying cacophony.

**Did the ordeal with the waterfall, stress you?**

**_You are safe now._ **

_You need to relax_.

**It scared you, didn’t it?**

**_Those bodies you found?_ **

_You need to forget_.

**You ran because you were frightened.**

**_You need not run anymore._ **

_You need to submit instead._

Stars does taking a nap sound so _good_ right now. Which is saying something, because Sans _never_ feels like napping. “it must take so much effort right now,” Sans hears Slim drawl, “if you have come this far. how long have you been trying? _how long has it been since you last rested?_ ” Sans finds it increasingly difficult to ignore Slim’s voice. It literally echoes and lingers in his skull like a fog, or a...spell. “ _resist me_ ,” their low voice lulls, despite the terrifying display of magic surrounding them. Sans trembles as Slim unbuttons his coat. Sans lurches weakly away, only to have Slim draw him firmly closer. “ _resist me, hero_ ,” they breath heatedly onto Sans’ cervical vertebrae. The brush of metal against bone surprises Sans, and his bones flush at the contact. As if nothing happened, his captor continues unbuttoning his coat until they expose Sans’ thinner layers.

Hissing, Sans wriggles in their iron grip, still desperate to get away. Sensing his renewed resistance, Slim turns Sans’ neck enough to expose the cervical vertebrae to the metal of their gold fangs. Sans immediately stiffens, before feebly pulling away. Gently guiding his skull so his vertebrae lay under their fangs again, Slim breathes over each one languidly until a tongue replaces their breaths. Sans can feel their free hand clenching at his ribs from beneath his sweater. Stars the chill of their phalanges feels _so—_

Cringing, Sans involuntarily groans at their touch. Embarrassingly enough, his soul responds with an exceedingly bright glow that lights up his ribcage. Whimpering, Sans curls inward to shield it. Despite the iciness Slim carries with them, their breaths and tongue lie hot against Sans. Equally warm magic in his mouth pools until it forms a tongue, and Sans can’t hide a moan fast enough.

“good,” Not-Papyrus praises, a pleased tone in their voice. Their fangs brush so close--and a sudden anxious thought of being bitten by those canines engulf Sans. “ _very good,”_ they sigh, hand slowly advancing up his ribcage. “it is as if you were _meant_ to find us...what do you think?” Whimpering, Sans tries his hardest to remember he needs to resist this stranger with his brother’s face. Unfortunately, Not-Papyrus considers Sans’s stifled sobs as a confirmation. His captor chuckles lightheartedly. “ _i think so too._ ” 

The phalanges grazing his sternum soon dance over his floating ribs, and Sans helplessly watches as Slim reaches inside for his soul. “ohh…” he hears a gasp, as Sans feels a steady weight over his shoulder. A heady scented magic replaces the old stench from before, one Sans can’t help but lean toward as Slim gazes at the brilliant display of light before them. Self-conscious and vulnerable, Sans draws back. To have his own soul out, and at a time like this! How inappropriate! How— “what a beautiful blue.” Heat engulfs Sans’s zygomatic processes. He attempts to hide his embarrassment, but his hazing eyelights can’t focus, and his skull lolls heavily against Slim’s shoulder.

Those golden fangs reflect the light of his soul, and Sans stares, watching the way the brightened blue refractions hang in the air. Like magic, he’d say, if not for his lightheadedness. “you have done so well,” Slim coos, and Sans blushes further at the praise. “you are already so perfect for him.”

“...F-for who?” Sans manages to pant. Perfect for their Lord? _His_ Lord? Distantly, Sans’ brow ridge knits in confusion. No, he bows for no one but his Queen. 

_Not yet,_ another voice replies in his head, and Sans shivers as the voice drowns out his thoughts. _A soul as faultless as yours is more than enough. A soul so full of love has room for one more._

_Will you accept another?_

_“Will you accept...me?”_ Disoriented, Sans stares, as the voice in his head converges with Slim’s.

“But...” he draws out through the haze in his head. “Why do you... _need_ me?”

“it does not matter,” Slim calmly continues, a shy smile across their teeth, “it is not for me to decide.” Gently, Slim returns Sans’ soul under his ribs, and it floats to its rightful place behind his sternum. Relieved and exhausted, Sans nearly collapses in Slim’s arms. 

He feels... _safe._ For once since he fell into this Stars-forsaken cave does he actually feel...like he isn’t alone. It doesn’t help that this monster looks so much like Papyrus. It doesn’t help that they feel like less of a stranger. “i know you are tired,” Slim voices quietly, the frightening predatory air from moments ago gone, “but i need you to do something for me. i will only do so under your express permission.” With what little energy Sans has left, he moves his skull in acknowledgment. Nodding, they lower Sans so his head leans against the inlet of Slim’s shoulder. “will you accept me?” they repeat. Through the fog in his head, Sans nods, despite his better judgement. “i need to hear it. tell me, will you?”

Stars their _voice_. How do they get it to sound so...soothing? Never in his life has Sans felt so exhausted to the point he had trouble speaking.

“...I will.” He swears the air around both of them warms as soon as the words are spoken.

“i am happy you choose to trust me,” Sans hears them utter gratefully. There’s relief, as well as joy in their voice. “i am happy...you are granting me this chance,” he hears them smile. With those gold fangs, Slim probably has a pretty smile, Sans decides. “i will make it right. i promise.” As their teeth brush against his temporal process, Sans’ breath catches in his nonexistent throat and he finds himself drifting further into the fog. _“sleep now_ ,” Slim lulls, like a guardian to their child, “ _and i will take care of everything_.”

Sans’ half-lidded stare fixates on the darkening amber of his ~~captor’s~~ (his Master’s? His friend’s?) beautiful gaze, and he exhales his compliance before everything around him goes dark.


	4. Chapter 4

**Summary for the Chapter:**

> Sans learns a little more of what he's gotten himself into. There’s more to Slim than meets the eye. Meeting the Baron means giving up your soul for a glance at him in the flesh. Too bad this only applies to Sans.

**Notes for the Chapter:**

> I'm grateful to all of you who've commented and gave kudos! I'm so happy my heart's bursting from my chest (as are my giggles!) XD

When Sans awakes again, a gentle breeze sweeps past him. His pauldron is fixed to his shoulder as before, with the rest of his clothes included. He leaps up, only to grab hold of a cowled fabric bunched up near a bony neck. Slim. The vampire regards him with tired sockets, and Sans only stares back. What— Sans’ teeth part to speak.

“You—”

“are you well?” they ask, “are you experiencing lingering dizziness, or suggestibility?”

“Wh—I—” A spark of tarnished gold lights in the chasms of their empty sockets.

“ _l_ _ay back down.”_ Sans starts to lay back in their arms when his brow ridge quirks at the ~~command~~ order.

“N-no!” he protests, jerking back up again. “Stop that!” At his renewed energy, Slim expels a breath, relieved.

“good. any disorientation?” Slim presses, “wandering hands?” Sans immediately snaps his hands into fists and holds them close to his chest.

“W-why?” he asks, worried. “What happens if I do?” Slim’s brow ridges knit, concerning Sans more. “What did you do—?!”

“post-hypnotic symptoms are not kind to certain subjects,” Slim explains quietly. “i need to know for certain if you experience any. i please ask you cooperate.” Taken aback, Sans cries out,

“ _I need you to tell me what’s going on!”_

“i will tell you,” Slim promises, “after i determine your mental state.” Sans’ eyelights shrink as his breath expels with a hiss.

“So you _did—_ ” Staring at empty sockets, a small gasp escapes from Sans’ teeth. Slim halts, floating mid-air as he cranes his skull in regretful acknowledgment toward Sans. 

“i am very sorry,” Slim apologizes, “i never meant to tamper with your mind. it has been too long since i have used my abilities last.” With a shake of their head, “it is... _unhealthy_ to use it all on one subject.” Sans, stiff in their arms, glances nervously up at them, relieved and disappointed to see their sockets void of those beautiful amber eyelights.

“I’m...not sure if I can forgive you just yet,” he grits his teeth. “I’m not even sure I _trust_ you.”

“your response is fair,” they quietly note. Slim carries him a few feet forward before Sans can’t stand it anymore.

“Can you please put me down?”

“of course.” Gently, Slim floats down and positions Sans so he could remove himself from their arms. Splashing into the water, Sans looks up again at them. Their empty sockets jar him still, but their smile seems genuine despite those intimidating gold fangs.

“Why—” Sans coughs, “Why did you save me? Weren’t you going to dust me?” Their sockets widen.

“ _dust you?”_ they inquire, surprised. “you never attempted to harm my lord. why ever would you think of such?” Sans fidgets with his gloves before looking up at them again.

“Those people,” he manages to blurt, “you killed them, didn’t you?” Slim cocks their head and faces him.

“they...overstayed their welcome,” they reply.

“What makes me any different?” Sans interjects. “Why spare me?”

“because we need you,” Slim utters. “skeletons are hard to come by, and the ones housed in humans are insufficient once stripped of their flesh. alone, they lack the magic. they lack the _spirit_.” A thought occurs to Sans, one that makes overall sense.

“You needed a monster—” Sans interrupts in realization. Slim nods gravely.

“my lord has been imprisoned,” they continue, “in a series of magically suppressive shackles i am unable to break myself. the layers of enchantment binding him are devised to prevent all servants of the dark from disrupting the magic. this in turn, leaves only servants of the light, or creatures in between as available candidates in its removal. but our few alliances proved inefficient, and none knew of our imprisonment in time to aid us,” Slim sighs. “m’lord and i collected more enemies than we did allies,” they admit, floating downward until their feet meet the water-filled floor. “yet you, who are of neither side, lifted the spell subjugating my lord’s consciousness.” Slim turns to Sans, who is becoming more bewildered by the minute. 

“Oh no,” Sans insists, “you’re giving me too much credit. I didn’t do anything—I was just in the wrong place at the definitively wrong time! I’m no more special than the next skeleton!”

“fate drew you to us,” Slim concludes, “to hypothesize your fortuitous qualifications as a result of mere chance—is evidence in itself of your importance.” Sans doesn’t understand what they mean by “qualifications,” and he ultimately doesn’t believe in fate, but there’s a suddenly serious look in their sockets, so Sans holds his tongue while Slim leans closer for emphasis. “in the duration you have awakened him and fled, my lord has been in a state of constant pain, and unable to maintain his physical form. as soul energy dwindles in unrelenting environments, it is apparent to remedy the damage while we still can.” They imploringly touch Sans on the wrist. A bat suddenly morphs where their hand once sat and Sans blinks at it, curious. “you are our one chance of salvation,” Slim iterates. “and now that you are here...i am ashamed to say we cannot let you go.” The bat latches over his wrists like a makeshift handcuff, inflicting a sense of betrayal over Sans.

“You don’t have to do this,” he chokes, frustrated at this back-and-forthness of Slim, how each and every time they’ve reestablished even an inkling of trust, they pull something completely and utterly unfathomed. “I won’t hurt either of you. I won’t run away—I mean,” Sans laughs aloud anxiously, “there’s nowhere for me _to_ go!”

“it is only a matter of precaution,” Slim assures him. “i would rather we go about it in this manner than more repressive techniques, yes?” Sans’ brow furrows. He still hasn’t figured out how they did it the first time. “truly i apologize,” they continue, patting the bat affectionately on the head. “i would not take such action unless i have no other choice. my lord is my world.” Sans catches the sorrow in Slim’s empty sockets, the furrow in their brow ridges. “i cannot part with him. you understand, yes? he is dear to me. after his freedom is secured, i promise i will do my best to maintain what little happiness i can offer you.” With a hopeful, sad smile, Slim touches his arm. Sans tenses at the contact. “you can find happiness with us, will you not?” His frown can’t get any deeper, and Slim’s hand retreats.

“This isn’t happiness,” Sans argues. “This is illegal. Look, under different circumstances I can understand but—” he moves his bound hands for emphasis, only for the bat to cry out. Emphatically, Sans stops. “—you can’t take my life away like that. You can’t keep me for your own selfish reasons. I want to stay because I _want to_. Not because I’m _forced_ to.” Slim’s stance stiffens, their lightless sockets about brimming with shame and guilt. The bat between Sans’ wrists squeaks in displeasure. Despite Slim’s previously confusing motives and actions, they seem like an otherwise nice monster. Despite how many times they’ve gone back on their word or betrayed him, Sans somehow can’t imagine Slim as someone terrible. In fact, if their meeting hadn’t been so botched, and other extenuating circumstances hadn’t occurred, Sans would consider them as more of an otherwise shy acquaintance. Sans can’t blame anything but his trusting nature in the end. “Please,” he insists, implores. “I’ll try to help you. It _doesn't have to be this way._ ” Nodding sadly, Slim puts a hand on his shoulder.

“i promise he can be a good master if you give him a chance. you may even grow to love him as i.” Sans frowns.

“We’ll see about that.”

\---

Slim leads him down the tunnels until they find the flooded chamber once more. Their mighty Lord, their Master… It breaks their soul to see him this way, to see him bound when he ought to be free. It isn’t fair. Slim hopes the skeleton understood why. 

To waste an opportunity as this would eat at what little of their soul remained. Slim can only hope he saw it their way in the end. It would be more merciful if he just played along. But if his inherent soul trait is indeed a dark blue, then it will take more tampering than Slim originally wanted.

To taint an honest soul would weigh a heavy sin.

To coax a fire from a flood proved an easier, more forgivable feat.

Still, Slim can’t suppress their instinctual drive to watch those lovely blue eyelights roll back, to witness them flicker away only to return with a jolt like static. Slim found it delicious, a mind ripe for the taking. They haven’t kept many a thrall while under their Lord’s service, but oh what fun they had otherwise.

Perhaps if Slim proves their good behavior, their Master will grant them this skeleton as a boon. They could keep him as happy and carefree as they desired.

A shame really, they did not catch his name.

\--

Whatever middle ground they have left is little more than attempts at bargaining and pleas to listen. Sans can’t think of another way to convince them to see there are options beyond what Slim ultimately decided. Surely they acted under their master's orders and knows for a fact Sans can’t feasibly stay here. To “maintain his happiness” won’t lessen his imprisonment. Slim in their concern for him, showed they have a gentler, more understanding side. Why else would they let him live? Why else would they opt for living handcuffs made of their own bats instead of suppressing his magic again?

Slim may have terrifying power, but if Sans can appeal to their kind character— Sans wouldn’t find it surprising if in another life, Slim inherited a green soul. Why they don’t have one now...worries him.

They don’t travel far, as they come upon the chamber with Slim’s lord not fifteen minutes away. The closeness doesn’t seem to surprise Sans, though part of him wonders how close they are to the spot he fell from. Almost at once, the notion dissipates, and Sans brushes it off as a passing thought. There are more important matters at hand, after all. He gave his word he wouldn’t run away, and Sans is moral-bound to his decision.

“come,” Slim bows and ushers him in.

“Wait,” pleads Sans, stopping before the threshold, “I want to ask. What happened to you...before you found yourself under your lord? Was your magic always that color? Were your eyelights?” Slim’s chin tilts upward so their sockets stray on the ceiling of stalactites. 

“no,” they reply, side-glancing Sans. “they were not. _i_ was not. but it is not my place to say. not at this moment. what occurred back then was an act of desperation, by a monster who no longer exists. perhaps...i will tell you. in due time.” Still so curious, Sans holds his tongue.

“Alright.”

As he steps inside, Sans notices the statue standing in the water instead of on the pedestal. In fact, it’s in front of him, with the shroud swept away from their face. Sans sees the snarl he initially suspected etched on their otherwise handsome stone face, and Sans’ eyelights follow the three deep crevices scarring their left socket. Horns with a slight curve at the end adorn their skull. A demon then. What else would have a vampire as their underling? Daring to steal a glimpse of their wings, Sans peeks behind their shoulder. He spies glints of feathers clustered atop the outermost bones of their otherwise draconian wings. A demon with angel’s wings…

So he wasn’t seeing things then.

Though just a head or so shorter than Slim, they tower over him and Sans feels small as he incredulously squints at the look of irritation in their eye. A small thought echoes in his skull, suggesting he ought to be kneeling, but Sans shakes it away. He refuses to bow to anyone other than his Queen. Stubbornly, he straightens his back to face the winged monster with pride. Slim silently follows after him, the water lapping at their robes.

“What do you want from me?” Sans calmly demands. The statue’s expression changes. Half-pained at the effort, a voice hisses from their stony grimace and echoes through Sans’ skull.

“ _I need you._ ” Sans winces, as their grating words rip through the air. 

“Why should I help you?” he questions, though part of him insists he stop while he still can. It might be Slim projecting the impulse onto him, though toying with danger is never a smart move, let alone with a force more terrifying than a vampire. The echo in his head compounds, startling Sans.

_“You_ **_have_ ** _no choice.”_ It’s like something grabs hold of Sans’ soul and slowly lifts him away from the ground. “ _Once you submitted yourself to my servant, you opened your mind to me.”_ How did—What was happening? This gargoyle wasn’t even moving?! “ _Once you came willingly to me, you forfeit your soul.”_ Sans gasps, cervical vertebrae straining to pull away from the invisible force tightening around them. _“Once you awoke me, you imprisoned your very being.”_ Sans is able to turn enough so his terrified gaze locks with Slim, as they stand just behind them, watching the exchange. Their relit eyelights fix on the fear in Sans’ sockets. If he could, Sans would cry out— _“Now you are_ **_mine_** _.”_ The weight of their will holds Sans captive, and it nearly squeezes all the breath from his nonexistent lungs. _“You_ **_will_ ** _submit to me,”_ they command. _“And fulfill your purpose.”_ That’s right ~~his Master~~ — _Slim_ needs him to… Distantly, Sans feels a tug as his soul manifests in front of him. Floating inches away from his sternum, Sans watches as the stone hands of the demon reach for it. Their mouth curls in a contorted smile as stone flecks give way to greyed bone. “ _Yes—_ ” they hiss, and once Sans feels their fingers curl around the cumulation of his being, he knows he can’t resist.

The demon drains him, like a parasite with a monster’s essence instead of blood. Sans swears he can hear his Soul as it beats chaotically in distress. 

“ _you are doing so well,”_ Slim praises, their bat loosening its grip around his wrists to climb atop and nestle on his shoulder. “ _please try to stay awake,”_ Slim’s voice warns almost through it, “ _my lord can be very demanding._ ” Breaths quickening, Sans watches fearfully as his magic drifts from his soul to the gargoyle, the dark blue bleeding into purple swathes as they come in contact with the stone.

He sees it again, in the light between their horns, a symbol. The flower. This time, the rings creating the petals split and dissipate as more magic feeds into the stony figure. Soon, the symbol itself is replaced by a ring of light that grows in size, as sheets of rock erode and fissure, enough for Sans to see a glimpse of bone and pulsating flesh underneath. Sans gasps, with eyelights rolling back as the invisible hold on his cervical vertebrae releases him. He falls heavily into something soft, and his boots graze the water with a small splash. Slim, he remotely realizes, as he blearily witnesses a regal figure emerge from the stone remains of their bodily prison. 

The imposing form shakes flecks of stone off of the dark purple flesh of their wings, and their cloven hooves crush a rock hidden beneath the waters. A low chuckle soon resounds into a triumphant laugh as the demon unfurls their wings. 

“ _Finally!”_ they grin widely, victoriously, “The Baron of Black-Keep has returned!”

\----

Slim clutches the limp figure in their arms as they rise to greet their Lord.

“m’lord,” they bow. Ah, how deliberate of their Lord, to straighten his spine proudly as he saunters to them. 

“Was I not _magnificent,_ Servant?” he bellows, “my entrance will surely inspire our new subject!” Proudly, he beckons to the new addition to their unit, only for his posture to deflate the moment he notices Sans asleep in his Servant’s arms. “Ah—” the Baron frowns, “I… suppose my majesty proved too opulent to comprehend! I cannot fault a servant for swooning so after witnessing such a dramatic return!” Slim smiles fondly.

“he will recover,” they assure him, “i will make certain of it.” Grinning, the Baron cranes his head to look over his Servant.

“You are looking well,” he smiles, affectionately brushing their shoulder with a hand. 

“i am pleased to say that time has treated you kindly as well m’lord,” Slim replies in turn. Still holding Sans to their chest, Slim leans their cheek into their Lord’s hand. The Baron strokes their face lovingly, and tilts his head forward. Sharp teeth brush Slim’s cervical vertebrae, and the Baron’s wings beat once to achieve the height needed to kiss his servant’s teeth.

“Tell me of our new acquisition, Servant,” the Baron grins. “I trust you have much to share.”

“ah, yes m’lord. he is a strong monster, much like you, and he shows promise under my direction.” The Baron nods, pleased.

“Marvelous. I trust we need not acquire victuals for you with him around?” Zygomatics tingeing a shade darker, Slim draws back to hide under their acquisition’s shape.

“i...i would think not, m’lord. but perhaps we allow him to rest before inducing another spell?”

“Right you are, Servant,” the Baron smirks. “We cannot have him dusting so soon. Why, t’would be a shame after all that work now, would it?” 

“yes m’lord,” Slim agrees.


	5. Chapter 5

**Summary for the Chapter:**

> Sans and Slim have a bit of a chat.

**Notes for the Chapter:**

> Thank you all so much for your patience! I ran into a bit of pacing trouble while I was finalizing this chapter, and it ended up becoming a lot longer than originally planned. It’s mostly talk, as well as minor world and character-building but I hope you still enjoy it!
> 
> The good stuff comes in a few more chapters, I promise. ;)

Groggily, Sans draws a hand to his temporal process with a hiss. This is perhaps the most times he’s closed his sockets in a given day, ( _has_ it been a day? Sans can’t be sure) and he _still_ feels so unrested. At least now he has an idea of how Papyrus’ sleep schedule worked. Though _his_ frequent naps did little for the ever-present exhaustion burned under Papy’s sockets. Unwilling to fall back asleep, Sans rolls over, automatically pulling the fabric draped over him closer. It’s oddly warm against his cold bones— Sans about throws the blanket off. He’s...where’s his sweater? His coat?! Sans pulls the blanket over his shoulders. His pants are still on, much to his relief; but his boots, his socks— After a slightly panicked search, Sans finds them drying just within reach. He also notices his kerchief, gloves, and pauldron neatly balanced on a rock next to where he’s laying. Sans sighs and slumps back, reassured by their presence. 

He’s startled when he hears a squeak. 

Eyelights lurching to find the source, Sans sees the otherwise large sockets of a small bat’s face staring up at him. It’s clinging to the top of the blanket, just atop the inlet of his elbow, and it seems to beam as Sans matches its stare. Sans squints at it, wondering where it came from when another bat crests from the folds of the blanket.

What in the Great White— 

Stiffening, Sans studies them. The partially melded bat extracts itself fluidly from the rest of the blanket, while the one on top crawls up Sans’ arm, with wide, gleaming lights in its sockets. These were like the bats Slim sent after him when he ran, Sans realizes. Now that they’re not chasing him, he can see they’re both primarily skeletal, with the exception of their fleshy ears and membraned wings. Curious, Sans reaches a hand out to touch the one on his shoulder. The bat nudges its head into his hand, and Sans is disarmed by its charm. It’s a little like that street cat that visits their abode, only a lot smaller, with bigger eyes and wings. The bat chitters, and lifts its wing so its thumb brushes against the top of Sans’ hand.

“H-hey little fella—” Sans gasps in awe, managing just barely, to hold back a squeal. “Stars, how are you so cute? I had no idea bats _could_ be this adorable—” There’s a light squeezing in his chest as he remembers smacking them away. “I—I’m so sorry I hurt you and your friends,” he apologizes. “I was scared.” The bat doesn’t seem to recall, for it nuzzles against Sans endearingly. The other one is resting on his lap, peering up at the exchange. “Stars,” Sans smiles delightedly, “you’re not so scary aren’t cha—”

“oh.” Sans stiffens. Slim. “you have awakened—” They’ve stopped at the entrance to this cavern, with Sans’ coat and sweater neatly folded under their arm. “i—i took the liberty of drying off your garments—” Slim stammers quickly, offering his clothes back to Sans. Embarrassed, he snatches them, hugging them close to his chest. The bats fly off their respected perches at the sudden movement, and the blanket slips from his shoulders.

“Why do you keep doing that?!” Sans cries out, “the longer I stay here, the more I think the worst has happened!” Their jaw gapes, as if looking to apologize but can’t find the proper words. 

“i only wished—” they begin to defend themself as Sans furiously dresses. Instead, they bite back their worry as they allow their tensed shoulders to slack, and their towering height to sag forward. “i understand your trepidation,” Slim utters carefully, shying away to give Sans privacy, “you are frightened. you doubt my intentions.” Their head lowers. “the empirical evidence you have gathered has only shown my capriciousness.” Slim’s long robes sweep against what little water has flooded this chamber as they make eye contact. “i also understand the last thing you must wish is to take an order from me,” Slim adjures, “so in accordance to this, i will instead emphasize the need for your swift recovery. it is imperative, and i can only hope i have assured you enough respite from your ordeal.”

Oh yeah, basically the exsanguination of his essence. The fact that Sans is sore but alive, means he must still have a good percentage of his soul left. He manages to slip his arms into the sleeves of his coat. After all the excitement and stress, Sans realizes he’s more tired than he thinks. Sans doesn’t bother with the buttons.

“What happened?” he mutters, leaning forward so his head hangs, hands bracing against his femurs. He considers laying back down with the blanket over him, but now that Sans is partially aware it’s made of dormant bats, he’s not so sure. Sans tries to push the thought away as one of the bats from before settles on his shoulder again. He vaguely hears the flap of wings as the second bat mounts itself just above the two protectively.

“you fulfilled your portion of the bargain,” Slim responds, a hint of melancholy in their voice.

“So will you take me back?” Sans voices raises, hopeful. He rises a little too quickly, and clutches at his sternum with a moan. He absently notices the second bat cry out from its roost in disapproval the same moment Slim involuntarily reaches out to steady him. 

“i cannot allow you to leave in such a state,” Slim protests, worry evident, “you are in no condition to undergo the ascent.” They’re so tall, even when Slim is slouching like this they’re still so imposing.

“I can still go—” Sans coughs, attempting to shrug them off, “Papy must be worried sick.”

“—your family,” Slim guesses, releasing him. “yes, i am certain they most likely will be. but they will worry more should you stumble to the surface half-coherent and magically unstable.” Sans considers this as he reluctantly seats himself again, propping up his skull with his hands.

Papy would freak out, obviously. Undyne would want to study him, figure out what happened. Alphys would interrogate him on who did that to him so she could beat them up.

Yes, it’s for the best if he waits, even though he has no idea how long he’ll need to.

“The...The Baron,” Sans fumbles for words, eyeing Slim from under his hand, “How is he?”

“in a better state than you, that is certain.” Sans finds it hurts to chuckle, like there’s a squeezing in his sternum. Like someone has wrung his soul momentarily dry.

“I—I suppose...he took a lot out of me?” Slim answers with a short nod.

“which provides further evidence it is best you rest.”

“As if _that_ would help,” Sans lifts his head to dryly scoff, “at this rate, he might as well suck me dry.”

“do not say such things!” Slim asseverates, “m’lord would never harm one under his protection, as i would not request it of you unless it were important.” Tone now quieter, Slim faces Sans imploringly. “my lord may demand more of you than you are able. the best method of circumventing him is to gather your strength while you are able.”

Sans _does_ feel tired, but in any case, he wants nothing to do with sleep. Not after all the trouble it’s caused him. Frustrated, Sans leans back. What’s he supposed to do when there’s almost nothing productive for him to do?

“What do you mean,” Sans’ brow ridges furrow, “is he thinking of taking more?” He manages to belt out a singular HA before curling into himself from the sting. “What’s left for him to take?” Sans grits his teeth, “my teeth? My bones?” A sudden laugh startles him.

“why ever would m’lord require your bones?” Slim guffaws, “there would be no room for additional placement on his body!” Did they just— Sans squints at Slim, astonished. “as for teeth, unless you mean for him to perhaps procure enough for an additional set, it is unwise to attempt bribing m’lord with them!” They just made a joke!

“H-he could, I dunno, wear them? Adorn his regal form with the bones of his most recent captive?” Slim seems to pick up on his sarcasm.

“alas, unless you wish to drape thyself upon m’lord, you must understand he necessitates you be as undivided as possible.” Sans can’t hold back a snicker. They...they have a sense of humor. Whatever part of him that still somehow thought of Slim as untrustworthy at this point is washed away by their cognizance. Sans steadily adjusts himself so he’s partially propped by an arm behind him.

“What happened to having me rest?” he teases.

“a moment in good humor is known by some healers to be considered as effective as medicinal substances,” Slim wisely supplicates. Sans has to stifle another laugh.

“Seriously,” he gasps, “where’s this all suddenly coming from? I thought you didn’t have a _humerus_ bone in your body.”

“well, to presume such is assumptive!” Slim puts a hand to their sternum in mock offense, seemingly missing the pun. “it may be outside of my place to banter with you, but seeing as how we lack innumerable methods of distraction, we must utilize what circumstances deem available.”

“Well, talking I don’t mind,” Sans confesses with a small smile. “But if you’re still thinking of getting me to sleep again, you’re out of luck.”

“it is only should you wish to yourself,” Slim replies, “as the catalyst to one’s healing process is determined by the amount of rest one allows themselves.”

“I mean, if you mean waiting for my magic to replenish, I can just dispel my eyelights or something.” There’s a pause between them, with Slim staring at him silently before they perk in realization.

“oh—much like me?” Sans nods when they point at their sockets.

“Yeah,” he smiles lightly. “Does it really work?” The thought of Slim’s gorgeous eyelights just out of reach doesn’t upset Sans as much as he thought it would. The fact that Slim is just interacting with Sans like conventional monsters do is a welcome relief, a taste of normalcy Sans doesn’t realize he missed. Slim returns his smile wryly. Laughing aloud, Sans adds, “How well can you even _see_ without your eyelights?”

“as well as one is able without the luxury of depth perception,” they reply. “though, my other senses allow me other means of visualization,” Slim grins sweetly. “you are...how do i say, like a beacon in the darkness. your soul is still so bright despite the amount m’lord took from you. and—” they look downcast, as if following an invisible string on the ground. “—it is sharing that light _with_ him.” A light blush creeps along Sans’ zygomatic processes. “at the state it is in, i am surprised it is not still at its brightest.” Sans leans forward, one hand on his lap while the other nervously scratches at his sternum.

“W-what do you mean?”

“your soul, since the moment you awakened m’lord, has been nothing but an overwhelming force. perhaps capable of exceeding even m’lord at his peak.”

“And not...because he’s got part of my soul, right?”

“oh no, you are powerful in your own right. you house a healthy soul, one unhindered by partiality and unmarked by deep tragedy. you choose to fill it with confidence, love, honor, positivity...most of which m’lord lacks.” They glance at him with a fond smile. “you remind me so much of him.” Despite the weird parallel, Sans smiles to himself, thinking their wistful smile quite endearing.

“What was he like when you first served him?” Slim chuckles.

“m’lord was so young. perhaps younger than you when he first found me,” looking fondly back, Slim smiles reminiscently behind their hand. “m’lord is very driven. his motivations stem originally from his father, as well as his legacy. m’lord works tirelessly, you see. to make a name for oneself when in the presence of hecklers takes time and precise patience.”

“Sounds like you really respect and admire him,” Sans observes.

“ah, i do read like a book, do i?” Slim titters lightly. “m’lord has grown to become so great, i find it difficult to not stand in awe of his accomplishments.”

“Is that why you’re sitting down?” Sans joshes. Slim covers their face, a light blush encompassing their maxilla. Though it physically pains Sans, his soul decides this exact moment to sing.

“heavens, i have not heard such humor in centuries!” they laugh aloud ecstatically behind their hands.

“At least that hasn’t changed,” Sans quips. “Wasn’t sure how different we’d be, considering whatever time you’re originally from.”

“what _is_ it like now?” Slim asks, “on the surface?” Sans takes a breath to lessen the tightening in his chest and smiles.

“A human came and freed everyone. Since then, we’ve been building a more permanent settlement for everyone to live. It’ll take time to migrate every monster from the Underground,” Sans adds ruminatively, “but we’ll get there eventually.”

“monsters? _underground?_ ” Slim cocks their head, confused. “in my time, monsters lived freely in their own right amongst other creatures, like the humans. and it was _them_ who feared _us.”_

“But—monsters have lived Underground until recently,” Sans’ brow ridges knit. “Just how old are you?”

“...i suppose much older than i appear,” Slim remarks. The oldest creature Sans knows is the famed historian Gerson. He easily lived through the sealing of monsters by the Seven Mages. He even wrote a book on it! By now, the tortoise is one anyone would describe as ancient. (Sans had never known another monster to have celebrated so many birthdays.) So if Slim remembers a time even _further_ back, well, that makes them ancient _and then some._ “ah...i wonder what befell of m’lord’s castle. it may be in ruin now…” Slim muses.

“You lived in a castle?”

“why yes. we kept busy despite being the two main inhabitants. oh...i hope m’lord safeguarded our belongings beforehand… t’would be a pity to see all those texts stolen away.” Sans doesn’t have the heart to mention he saw no castles when monsters first began ascending to the Surface. “but ah, enough about my mutterings,” Slim smiles, “i request you tell me more.”

“About what?” Sans asks with a slight smirk, “me?”

“why ever not?” Slim asks, interested. “it has been centuries since i have conversed with another apart from m’lord. excluding the imprisonment of the monster populous underground, how have they advanced? have they evolved?” Sans thinks a moment. “have you dragons?” Sans glances at them, confused.

“We have reptilians, elementals...animal monsters...slimes, Temmies—” Slim deflates noticeably at this news.

“but none like m’lord or i…” 

“I’m afraid not,” Sans shakes his head. “Though...the lineages from your time may still be present in us, just in small quantities. Maybe even shows up in some of our abilities. I read a speculative article about how reptilians retained the physical colorings of their dragon ancestors, while elementals got to keep the forms. They’re more compact. The ones I’ve met are around my height or taller, but not enough to fill an entire house.”

“amazing,” Slim gasps gleefully. “for the populous to diverge as such!”

“What kind of monsters were in your world?” Sans inquires, curious.

“oh we had many a creature,” Slim begins excitedly, “the noble dragons, trickster spirits, sirens, fairies, creatures of the dark like m’lord and i—”

“If you had demons, you must have had angels too—” Sans realizes. Slim’s face falls slightly at the observation.

“ah...yes, they were present as well,” they reply nervously. “though, our experience with angels has not...been the most ideal.” Sans studies their face a moment before dropping the subject. No point in upsetting the only one who at least acted like they cared for his well-being.

“So uh...you said there were others? Were they like you?”

“ghouls?”

“No,” Sans shakes his head, a furrow in his brow ridge. “You mentioned you had allies? And they couldn’t help you in time.”

“ah, yes,” Slim recalls, “our allies of shadow and light. i did have a volunteer, but outside factors prevented his involvement. though i consider him kind to willingly aid us, i understand why he was barred from it. as m’lord sharing his soul with a fairy would have ultimately not been a wise decision.” Sans cocks his head and frowns at the thought. Fairies and demons are in such opposite sides of the spectrum, he doesn’t think it possible at all that the Baron could get along with one. 

“You know, that _does_ sound like a terrible idea,” Sans chuckles despite the slight heave in his chest. Slim smiles lightly. 

“even if i were to accept his offer,” they muse, “they were on equal ground by then, and to take of him would have been against m’lord’s wishes. one cannot say the outcome should we have found another so prepared to freely give,” Slim sighs. “still, to have you here now is a gift i could only have dreamed of.” 

“ _Do_ you even dream?” Sans asks, curious. Slim leans back, in a thoughtful gesture.

“i...do not suppose i know,” they reply. “i have not properly dreamed since i was turned.”

“So...what _do_ you experience?” Slim fingers their robes, phalanges curling into the fabric of his cowl.

“sensations, most often,” they finally answer. “distant ones. if i allow a number of bats to separate from my main body, i hear what they hear, see what they see. often, should i stand as a ceaseless vigil for m’lord, i listen for the vibrations and beat of a soul. otherwise, when i am at rest, there is only darkness. there is naught but the void.” Sans can’t imagine not dreaming, so there are times he knows it would be a mercy to just sleep. Given how little he tends to though, he doesn’t think it’ll matter much.

“Do you ever think about where your friends would be now?” Sans asks. Slim blinks, their sockets seeming darker under them than usual.

“i...have not,” they admit. “besides those unexpected guests, none have found us after all this time until you. i cannot say i am angry with them, because deep down if i knew i could not aid another, even one i considered a close friend, i would not do it. to leave with them would have meant entering a world where i would only know either ravenousness or death. to leave m’lord alone would have destroyed me. to abandon m’lord would have deemed his life less in importance as mine. and if he managed to escape the confines of the spell, no one would take care of him. none would understand him. to allow him to suffer out of a selfish desire to avoid the worst would have killed both of us in the end. whether it be through the sun or a sword.” At this explanation, Sans discovers he was rocking while listening.

“You’re...you’re very devoted to him,” he realizes, halting his movement. “I guess if you’ve been with someone that long it starts to mess with you a bit.”

“you only know what you have seen,” Slim replies graciously. “to know him as i have, as both a companion and my master, as a lover and a friend—” Sans swears he hears a contented sigh in their voice at the last two examples, “—he is more than he appears,” Slim finishes. “there is more to him than what he chooses to reveal.”

“Of course you’d say that,” Sans scoffs, not unkindly. “If you still consider him as a friend after all that has happened.”

“i have cared for m’lord, looked out for him, and in exchange, he has given me everything i could possibly want. he has granted me the second chance i did not deserve,” Slim smiles shyly to Sans. “if that is not what a friend does, what do you consider a friend to be?” Sans blinks, hands on his knees.

He thinks about Undyne, and how she’d watch those cartoons with him whenever he needed time to chill but didn’t want to do so alone, how she’d listen to his rants about cool science facts or how Human technology could mesh with monster magic—and how he’d do the same for her.

He thinks about Alphys and how she’d throw snacks at him if he trained a little longer than he said he would, how she’d yell at him to go home if it was running late, and how she’d be the first to call him so they could watch the newest Napstaton music video together.

Lastly, he thinks about Papyrus, and how he’d take him to the bakery to treat Sans to a small dessert for a job well done, how Papyrus would give him the bigger half when they decided to split something with their extra money. How despite how tired he always was, Papy spent at least one of his days off with Sans because he knew Sans needed it.

Thinking of them now sparks a melancholy in Sans. A faraway loneliness.

The bat on his shoulder nudges its head into his cervical vertebrae. Sans idly strokes it with a finger and it chirps contentedly.

“Friends share parts of themselves with you,” he thinks aloud. “They’re there for you, sometimes for only what you think you need, and sometimes, in ways you didn’t think you needed. They...care about you. And they show it in different ways. Friends...” Sans exhales, as if having difficulty remembering or wording his thoughts. “...friends know when to leave you alone, and when you need to speak your mind about a problem. And, when times are tough, they have different ways of helping you out.” Sans looks to Slim, hands open, hoping they’d understand. “And...your fairy friend? I think he had the right idea, wanting to get you out, but didn’t want to hurt you by separating you from the Baron,” he reasons. “He had to have cared about you both if he bothered to try.” Slim stares back with contemplative sockets.

“i have much time to ponder this, and i do agree. to take his offer without discussing it with the others also involved would have been selfish of me. deciding without m’lord’s consent would have been a mistake. and...if i were wrong and took his soul recklessly...” Slim’s gaze lowers. “i would not forgive myself.” Their tall form shakes under their robes. “i would have lost both an ally, a friend, and all those connected to him. and to even consider stealing his light from them would only result in a torturous end.”

“Hey,” Sans puts a hand on them, and they jump, startled. “You’re here now. And, wherever he is, wherever he ended up, I'm sure he had a happy life.” Slim glances at Sans before offering him a timid smile.

“outside of our unusual predicament,” they query, “would you consider us friends?” Sans furrows a brow ridge at this.

“I barely know you Slim,” he says, flummoxed.

“does not mean you will continue to shortly,” they grin, shy yet mischievous. “now, where was i?” Slim sits in front of Sans, empty sockets beaming. “should you wish to continue conversing, ask me what you wish,” they offer. “i will answer truthfully.”

An unprovoked thought occurs to Sans that he can ask Slim anything; about their powers, about the Baron and how they came to be trapped. Slim seems the type to answer anyway, as they seem quite friendly and willing otherwise. Despite their unfortunate first encounter, Sans can’t find Slim ultimately at fault in the end. Perhaps he can get to know them better with this opportunity? The second bat lands on him from where it previous roosted and climbs up his other arm, its small claws digging into the upper sleeve of his coat.

“About your abilities,” Sans decides to ask, idly aware of it, “are you just... _made_ of bats?”

“oh i am contrived of an entire colony,” Slim smiles, restrained yet gleeful at this chance to make conversation. “you witnessed them when you threw me into the water.” Sheepishly, Sans stiffly smiles.

“Uh...about them though. When they get hurt, do you?”

“the injury is diffused between areas of my main body, but overall the answer is yes,” Slim replies simply, “they are a part of me. they _are_ me. transitively, what happens to _me_ shows in _them._ ” Well shit. Sans’ soul sinks at the verification of his initial suspicion.

“So that time,” Sans thinks back haltingly, “When I reached the waterfall. I heard them _warning_ me. Was that you too?”

“ _yes_ ,” Slim grins widely, elatedly. “why, it has been years since anyone has reported distinguishing their voices. their internal vocal structures are so small. most often, others hear nothing more than a squeak.” Hm...

“So uh...is your consciousness divided into them then or…?” 

“i am fully aware of my bats at all times,” Slim answers, “yes.” Oh… Sans’ expression freezes into an uncomfortable smile. OH. His entire skull flushes a deep blue. OH NO. 

_He called their bats cute—ohhh Stars did they hear him—?!_ In an attempt to wave away his embarrassment, Sans changes the subject.

  
“And that _paralyzing spell,_ ” he interrupts, “what _was_ that? Blue magic doesn’t bind or prevent the flow of another’s magical capabilities. So how did you do it?” Slim’s sockets stare a moment, and they look down in thought.

“would you believe me if i admit it was not what you thought it to be? that it was but an illusion, constructed by your mind to distinguish what was happening to you?” Sans goes rigid, and Slim continues, “my powers longed to be used, and…” they chuckle nervously, “as you were the only pliable subject nearby…” Sans’ soul catches in his throat.

“You—but _how?_ I thought you needed to _want it_ to be...to be—”

“what ever do you mean?” Slim asks innocently, “you proved a lovely subject, submitting to me as you did.” **_Stars_ **—Sans’ face grows hot as his blush deepens.

“Can we _not_ talk about that?” he requests feebly.

“but...did you not _enjoy_ it?” Slim asks, genuinely curious.

“ _I didn’t have much of a choice now, did I?”_ Sans snaps, then immediately regrets it when he sees Slim flinch.

“it is...difficult to ignore the drive to when one has neglected it for so long,” Slim stammers, “i... i am still so very sorry i did so without your consent. i am sorry for frightening you.” they exhale sharply. “i took the initiative because i feared you would take such drastic measures again.” Sans’ gaze clears in realization.

“When I let the waterfall take me—” Slim’s head bows.

“when i realized what you chose, i dove in after you.”

“You were...mumbling something,” Sans recalls. Slim nods.

“i was preparing a spell. for when i reached you, i needed a moment to disperse the impact. we were falling quite fast.”

“But—how did—the bats? Can they even _swim_?”

“do not worry,” Slim smiles timidly, “they are quite hardy, small as they are. a little water would not hurt them.” But...if that was case, then—

“So you’re saying you did it to protect me?”

“why, of course,” Slim replies immediately. “your safety became my responsibility the moment i knew you were more a danger to yourself than i. you became my priority once i was ordered to return with you.” They take a steadying breath. “for all our sakes, i needed you intact. to do nothing would have only caused suffering between both parties.”

Sans puts a hand to his teeth. Slim doesn’t _seem_ to have the aura of someone blindly following orders. Why else would they have put so much effort on rescuing him otherwise? They must have something to gain from all this besides how important this Baron is to them. But to go about it the way they did… 

“Restraining me with magic I understand, but why did you gag me?” Slim’s gaze lowers sheepishly.

“this is... _embarrassing_ to admit but—” they offer him the smallest sheepish grin, “—i needed to see for myself the condition of your soul.” Sans flushes. “to bring out one’s soul without endangering them in conflict requires more... _intimate_ measures.” Oohh Sans doesn’t know if he wants to hear this—

“Is—that why you tied me up? Why you—” Sans momentarily hesitates, “—grabbed me by the clavicle?” Slim turns away, ashamed.

“to convince you or have you otherwise protest was out of the question,” they explain, “i used the most efficient methods i knew with much success.” Utilizing fear is a known tactic to Sans, but the other… He shuffles back as far as he can with the wall behind him. 

“Were you—” Sans gulps, “—appraising me?” Slim nods.

“by all means,” they confess, “for my lord to renew his lost strength he required someone with equivalent vitality. as i discovered, you had more than enough.” Sans doesn’t like the sound of that. It makes him seem barely above chattel.

“But—he’ll give it back, right?” Sans fearfully objects, “my soul?”

“m’lord is a noble monster of his word,” Slim assures him, “he will not take without returning what is owed.” It’s too early to know when Sans will be recovered enough. It’s too late to try and do anything drastic, especially when Slim did so much to save him. Not to mention what they seem to do for their Baron. The mere thought of the demon sends Sans’ in a strange tizzy, and he blurts out an unrelated question to keep his mind off of him.

“You don’t have wings too, do you?”

“not always,” Slim smiles. “but when they are required, i do use them. would you like to see?”

“Please?” Brushing down their robes, Slim stands and unfurls their arms. Sans looks down in time to see the bats making up the blanket detach and weave themselves into Slim’s robes to create a pair of membraned wings much like the Baron’s. Sans gasps. “Oh—” he breathes, “they’re beautiful.”

“i thank you,” Slim blushes, sweeping them forward so Sans can touch them. “i do not use them often, as they serve few purposes and expend my bats more than necessary, but they are useful when required.”

“Oh,” Sans remarks, as the wings disintegrate into individual bats, “like my magic?” To the Baron, he wants to add.

“yes,” Slim nods, as the bats that don’t meld into their robes reform into the soft blanket from before. “as we have resumed discussion of the topic, i must leave you to rest.” The blanket falls unceremoniously across Sans’ shoulders. Stunned, Sans watches them walk away, the action suddenly inducing a rising panic in Sans.

“No wait—” Reaching out to them, Sans catches the barest edge of Slim’s retreating robes. “Stay with me?” he requests, “Please?” Empty sockets stare down at Sans, surprised. “I know you’re the last monster I should want to be around,” Sans confesses, “but you’ve been kind to me Slim. I don’t know how I feel about the Baron just yet.” Stepping closer, a gentle smile blossoms on Slim’s face.

“my lord may be a fearsome sort, but he is no stranger to hospitality,” they assure him. “should you wish to seek an audience with him, i will gladly escort you.” 

“I don’t even know if I want to _see_ him after he literally sucked up most of my soul,” Sans cringes. The laugh that Slim belts out is lively and lovely.

“if you wish me to stay, so be it,” they regard him intently. Sans loosens up immediately with relief.

“Thank you Slim,” he breathes gratefully. “I still don’t know how to take all of this,” Sans admits sheepishly, “this wasn’t really how I was hoping I’d spend my evening.” Slim brushes at their neck.

“what is it you planned instead?”

“To see my brother,” Sans smiles to himself, “he wanted to meet with me, said it was a surprise. He told me he’d be at the park, and I was in a hurry.” Sans puts his thumb to his teeth to hold back an anxious grin. “Didn’t think of my glasses until I was already almost here.” Wistfully, Sans eyes the stalactites above him. “Strains my eyelights,” he mutters, “to keep squinting like this.” Sans exhales loudly after a pause. “I wonder if he’s thinking about me,” he draws his knees close and hugs them. “I wonder if he figured out where I am. I mean, I was able to talk to him beforehand, but that doesn’t mean he knows where to look.”

“you speak of him with as much hope as you do doubt, ” Slim observes, taking a seat next to him. “is he not quite devoted to you?”

“Well,” Sans laughs nervously, “he can be a little too worrying. He acts like I’m not a capable monster sometimes. Treats me like a child.” He finds himself frowning, oddly resentful. “Everyone seems to.” The silence that hangs between them is heavy, and Sans anxiously turns away, embarrassed at his admission.

“do you believe yourself to be a capable monster?” Slim asks, breaking the silence. Sans hesitates. “if you choose to discredit yourself, know i will refute your denial with examples of my own observation.” 

“Wh—”

“with what i have witnessed, you are more than capable,” Slim voices in all seriousness, “you exceed what one would expect a knight to retain.”

“I—uh, train under the current Captain of the Guard herself,” Sans scratches at his cervical vertebrae bashfully.

“then you are a knight in your own right,” Slim’s sockets widen in awe. “more than i would expect from a modern monster such as yourself.”

“Well—” Sans stammers, “we don’t really need to maintain our original training regiment anymore, since we’re not at war with or planning anything against the Humans, but...there’s something comfortable about the routine,” he admits. “There’s something about it that really grounds me. Training levels my head. It calms me.”

“physical activity is a quite engrossing and robust pastime, a regulatory one beneficial so long as you pace thyself.”

“I hate staying still for too long,” Sans confesses. “Makes me nervous. I feel like I ought to be _doing_ something—” he sighs, “—but now I can barely stand without my chest hurting or feeling the slightest bit dizzy.” There’s nothing left to say on the matter, Sans knows there isn’t. Slim already apologized, yet a gloomy air hangs around them, like they’re trying to atone for a sin.

“if you are faint, perhaps you ought to lay down,” Slim suggests. Sans absolutely does not want to, but inwardly he knows they’re in the right. Reluctantly, Sans lays down with a sigh. The bats cling to him where they’ve settled, one on his chest, the other nestled near his mandible. When they decided to spawn from the blanket, Sans doesn’t recall. He does feel a little better though, both in seeing them and the act of reclining.

“I’ll have you know you’re right and I’m extremely unhappy about it,” Sans exhales.

“we cannot always be in constant strain,” Slim gently smiles. “though there is much to do, there is only so much time, especially when it comes to rest.”

“Yeah, yeah,” Sans rolls his eyelights. “Starting on the road to recovery and what not.” It’s silent between the two as Sans adjusts himself best he can on the rock he’s laying on. It’s not comfortable in the least. Sans wishes they weren’t in a cave. He wishes he had the strength to just get up and leave. But he can't, and if Sans knows anything of himself, it’s that he keeps his promises. He just has to see to it that both the Baron and Slim are held accountable—

“what is it like,” Slim nearly whispers, disrupting the uncomfortable stillness. “above us? what lies beyond our cavernous prison?” Sans glances at the ceiling reflectively.

“There’s a large expanse of grass and foliage,” he recalls, “trees too. Like the kind we had Underground. Pines, I think they’re called.” Sans smiles fondly. “The sky is clear on most nights,” he murmurs, “you can see the stars. And—” he catches himself sobbing, “—it’s very beautiful on the Surface.” Sans takes a moment to wipe his infraorbital foramen with the back of his hand. “When the Barrier was dispelled,” Sans smiles sadly, “we lived in the woods in the wake of the mountain. Along with the Human who freed us, a few of us journeyed to the closest establishments of Human government to inform them of our arrival.” A sigh. “When it felt like we finally made a new home on the Surface, we learned the place we moved all our homes and businesses to was considered a protected park to the Humans, not a place to house an entire population of monsters. And...we had to leave it.” A pang of longing. Sans’ chest hurts more than it should. Perhaps it’s because of how burdened it’s become. Two monsters are using it now, after all. It’s almost like it’s physically straining to feel.

“...where have they settled you all?” Sans wipes below his nasal aperture. 

“The Humans weren’t as accommodating as we hoped, but they set us up with temporary housing and began registering everyone so we could eventually claim our full citizenship.” He scoffs tiredly. “Which is ridiculous, by the way. We were all born and raised on this earth alongside them. It’s the same world. Why do we need to prove ourselves in order to be considered legitimate?”

“it is perhaps a method of control in the form of their standards in maintaining their government, as well as the initial populous,” Slim muses. “much like how one were to prove their noble birth by claiming a deed or accomplishing the impossible to establish their worth to those who will listen. they cannot declare their triumphs by speaking of them alone. they require the testimonies of others to bolster their reputation. they require evidence. they require more than just their inherited title. to become accepted, to truly belong in the eyes of others, you must be ready to put aside your pride and choose a difficult, but humbling path.” Sans’ brow ridges furrow.

“That was...really insightful,” he comments. There’s more to this than Sans realized, not just to the constant ache beneath his sternum, but also to this whole endeavor. Sans can’t shake a growing feeling of guilt at his participation. “Slim?” They politely offer him their attention. “I’ve changed my mind. Can I…” Sans swallows dryly. “Can I talk to him?” Slim’s sockets widen with a suppressed excitement. “I need to ask the Baron something important.”

“why ever not?” Offering a hand to Sans, Slim regards him intently as they rise. “perhaps i will use this opportunity to introduce you,” their smile is timid. Sans flushes as he takes their proffered hand and they carefully help him up. “properly, this time.” As Sans leans on Slim for support, the bats that made up the blanket return to their rightful place in Slim’s robes leaving behind the two from before. Slim doesn’t seem to notice their insubordination. Perhaps they left them there on purpose? The bats are slightly roused by his jostling, but are otherwise undisturbed. Despite what Slim might also need them for, Sans can’t help but wonder if they meant this as a source of comfort. He can’t help but think the bats are there to help him.

With all things considered, Sans doesn’t want to admit it, but they do.


	6. Chapter 6

**Summary for the Chapter:**

> Sans speaks to the Baron.
> 
> The Baron and Slim spend some time alone.

**Notes for the Chapter:**

> Thank you so much for waiting! I tend to work two parts at once for continuity's sake, so if it's been a while since I've last posted, it's because there were still some kinks I had to fix up (haha)
> 
> The next chapter has what you've all been waiting for: some steamy smut. ;)

They’re no longer in the same chamber the Baron was originally held in, and Sans can tell. It’s more spacious than the prior, slightly smaller than the living room of Sans’ Underground home. Though most natural caverns tend to vary, the most meaningful difference Sans can garner is the room the Baron was held in, for lack of a better term, was the only place with carved pillars jutting from the cave walls. Like his detainers were treating him like a prized conquest none were allowed to witness. A trophy for only time to behold. 

There’s evidence of unnatural areas of smoothness here, like someone tried to carve something from the rock-face, but abandoned it midway. Sans can only speculate the intention of the mason. Were they trying to decorate? Make this chamber more structurally sound? Was this supposed to be part of the Baron’s original prison? Slim’s?

This cave has been explored through, from what Sans can make out, there’s evidence of it. There were definitely others who have been inside before, albeit in the distant past, if not give or take a few decades. The Baron upon his pedestal was fairly preserved despite the dampness. It may have been because of magic. It may have been from anything.

Inwardly Sans wonders if the magic that petrified him still lingered in the pillared room despite Sans’ arrival supposedly breaking it. Or that perhaps the Baron tired of the place. Sans would be sick of it too. Any change of scenery is usually considered a good thing, especially after a supposed few centuries of mundanity.

There’s probably more to the spell than him can fathom, if just Sans showing up started all this. But Old World magic wasn’t his focus of study, neither was it one most monsters were to delve in since their imprisonment Underground. Monsters of his generation were all so keen on the future, on how they could survive and thrive. How everything would be different once they were back on the Surface. Why would they want to think of the past when elders like Gerson chose to for them?

Slim practically glides up a sudden incline and it isn’t until Sans nearly trips on a step that he notices a few feet from the entrance of this cavern are jaggedly formed stairs rising from the water. Confused, Sans turns around to inspect the ground behind him in what he could only describe as the hall. Was this here before? The bat clinging to the front of his coat eyes him with reignited bright eyelights, a puzzled expression in its sockets.

“Sorry buddy,” Sans apologizes, pivoting to catch up to Slim. Those looked a bit like flowstones, maybe a sinter terrace? Sans can’t be sure. Why hadn’t he seen this area before? Sans chalks it up to inattentional blindness from the time he was looking for places to escape. This clearly wasn’t important then. Maybe if he puts in the energy, Sans can explore these passages a little more.

If he stayed for that long.

A gentle hand on his unoccupied shoulder brings Sans’ attention back to the matter at hand. He’s here for a reason. Sans inhales slowly and trails after Slim, idly stroking the bat clinging to his coat.

The nearer they are to the Baron the more Sans discovers he’s towering atop those cloven hooves. Now that Sans can study him at a safe distance, he can see the Baron is just a head or so shorter than Slim, but still effectively a giant compared to Sans. Both of them being skeletal doesn’t seem to help. With how old he’s guesstimated them both to be, Sans concludes that skeletons and their variants grew less densely than the modern monster. Though how they both came to be so tall is a mystery, until Sans looks down and catches a glimpse of Slim’s legs. They’ve aged like bones are wont to do, worn by the water, streaked with an unnatural film. It’s evident in the way Slim leans, how ashed their bones have become. How much of them had been eaten away by time? How much magic was sacrificed to sustain what little of their body was left? With what bones Sans can see, Slim hides their erosion well, under the guise of their long, flowing robes. The Baron seems to do likewise, only using the effectiveness of layered clothing.

The Baron though, seems to have been granted the boon of health. His back is facing them, and he’s examining the cave wall, as if there’s something of interest there. The exposed bones on his wings and tail are less grey, and more preserved, practically the same as Sans. It could be because Sans’ soul rejuvenated him to some extent. It could be from the petrification spell. With Slim, Sans steps closer. 

To look up at the Baron brings forth a sense of fear and wonder over Sans, as well as awe and disgust. Seeing him in the flesh, the Baron seems to give off a pretentious air that doesn’t sit too well with the usual company Sans prefers. Unlike his beloved Queen, the Baron is less regal, more unrefined. 

Granted, he _has_ been locked away in stone for Stars-Knows-How-Long, and he’s from a time older than the Queen herself, but...he’s just not what Sans expected. It’s the way he stands; his overly straight posture, the way he’s craned his neck so his head is cocked in a domineering fashion, how he holds his shoulders widely—that gives away his character the most. It’s even in the way his skeletal tail widely arcs when it moves. 

From what Sans gathers, the Baron is arrogant and prideful, not to mention haughty. Sans grits his teeth, trying to hold back his own prejudices. But he can’t help but feel anyone can see that the Baron just _exudes_ bad news. It’s not just the fact that he clearly thinks so highly of himself, it’s that Slim paints him in a better picture than Sans would have liked. Sans would say he’s disappointed with this outcome. 

Were it not for Slim’s decency, Sans wouldn’t have considered seeing him at all. The fact that it’s Slim who convinced him they were reasonable despite what desperation impelled them to do just drove home how much the Baron truly relied on them. And if someone so great still considers someone like Slim beneath him, well, that just doesn’t sit too well with Sans. 

The bat on his shoulder nudges at his cervical vertebrae with its thumb claw. Sans exhales and frowns. If that was Slim cueing him to reconsider, they’ve picked an opportune moment.

Despite his initial misgivings, Sans can’t bring himself to hate the Baron. Not for lack of trying, but more because Sans suspects Slim planted a small suggestion that took root deeper than Sans would have liked. Part of Sans doesn’t bother trying to accuse Slim though. If anything, they’re just trying to help. By acclimating him. Or something. Lucky for him, they both haven’t tried to do anything else as of yet. If they do try something while Sans is in his current state, Sans isn’t sure he has the strength to fight them both off. Well, he could _maybe_ land a punch on the Baron if he gave himself a head start. Sans grins privately at the thought, but Slim probably wouldn’t appreciate a gross misconduct of his own doing. Not to mention how tactless and embarrassing that would be if Sans were proven wrong.

“m’lord,” Slim bows. “if i may introduce our new acquisition to the baron of black-keep,” they step backward, so Sans is presented to him. “he wishes to seek an audience with you,” Slim finishes.

The Baron turns and Sans catches a peek of his purple gaze from over his leathery, semi-translucent wings. Sans blinks. The wings fold, and Sans witnesses the square of his jaw shine prominently, framing his sharp teeth in a... _devilish_ fashion. (Stars damn it, Papyrus would be proud of that one!) From this angle, he can see up close the three long, partially healed scars on his left socket.

They are all jagged, like the thing that clawed him managed to rake into his face only because of a mistake in proximity. They aren’t deep enough to cut through the bone of his maxilla nor his socket, but the middlemost one does exceed almost onto the curve of his frontal bone. Two majestic horns closely curve atop his skull, and Sans has trouble not noticing the faint halo of light circumventing his skull just so.

Sans blinks again, to look at something of the Baron that _isn’t_ his face. He decides to settle on the brooch attached to his frilly ascot. It matches the deep purple of his glowing eyelights. But then Sans heats at the thought of them glowering down at him. His gaze descends to the only slightly crumpled greyish-purple waistcoat hugging the Baron’s broad chest. Sans almost doesn’t catch himself staring until he swallows and realizes he’s blushing.

Stars the Baron is... _quite_ attracti—

Sans slaps a palm over his face to interrupt the thought.

This is _business._ **_Business!! Only!!_ **

Stepping forward, Sans straightens as tall as his body will allow. Despite how short he is compared to these two monsters, he wants them both to take his request seriously. Studying him, the Baron’s wings fold behind him, and his long bony tail swishes as he looks Sans over.

“Magnificent,” he expresses, purple eyelights brightening with awe and pride, “and such a speedy recovery. I would expect no less from our new acquisition.” Sans’ blush deepens as he takes a stride and nearly trips on his own foot. The bats stiffen as their eyelights immediately ignite, while both the Baron and Slim’s sockets widen. But when Sans barely manages to catch himself, they all visibly relax. The vague hum of magic dies.

“Are you well—?” the Baron leans forward to examine Sans. Stars Sans doesn’t want his attention right now, not like this! 

“m’lord if I may correct you,” Slim interrupts, mercifully sparing Sans the Baron’s scrutiny. “he wished to seek you earlier in his recovery.”

“What?” Addressing Sans with surprise, with realization, “you ought to be resting—”

“I—” Sans straightens, and clears his throat to start over. “—I want to see it,” he tries again, “Am I allowed the privilege to see the other half of my soul?” The Baron’s skull cocks at his pluckiness, but decides better than to chide him.

“Why ever would you not?” The Baron inquires, with a dignified tilt to his chin. His response catches Sans aback.

“I just—” he stammers, words abjectly failing him, “—didn’t think you’d _let me_ , y’know? Technically it’s still got some of your soul in it too.”

“Oh!” The Baron taps his temple like he forgot something, “How witless of me! You have considered my personal stance on the matter! What a caring one you are!” Sans’ brow ridges immediately knit.

“Are you—” Sans shakes his head, choosing to ignore the tone he thinks he heard. “Nevermind. May I see it please?”

“Certainly,” the Baron complies. “Though if you wished to see me unclothed, luck may have granted you the opportunity in a more private setting.” At this, Sans blushes and turns away.

“Just—my soul. Please.” The Baron privately grins at his reaction.

“As you wish.” The Baron cups a hand to his chest and lowers his head a moment before drawing out his soul from his sternum. Awash with streaks of dark blue striping throughout the center, the exposed purple soul of the Baron beats calmly as it floats above his metacarpals. “Is it not in a satisfactory condition?” he asks, watching Sans’ stare fixate on the intermixing of colors.

“It’s—” he pauses, taking it all in. The magic courses steadily, the blue flowing with and alongside the purple, yet still separately defined. Compared to what his soul’s state must be, the Baron’s is absolutely radiant, practically shimmering with a resplendent air. It’s beautiful, much like any healthy soul would be. But seeing it outside of himself, as a part of someone else, his soul is more than enchanting. It’s like Sans is seeing it for the first time with brand new eyes. “...you're taking care of it, right?” Sans utters aloud.

“Why would I endanger your soul?” the Baron questions, “It is not mine to abuse, thus the notion is inappropriate to entertain.”

“But—” Sans feels like he’s missing something important. “is it even still mine when it’s mixed with _yours?_ ”

“Of course it is!” the Baron asserts, “If my housing half of your soul is your worry, know that it is only a temporary measure. Besides, in your current state, you are in no condition to accommodate it.”

“Because you fucking took it without asking!” Sans yells. The Baron gasps in offense.

“Such a tongue on this one!” he snaps reproachfully. “Such behavior is evidence in itself.” With that, the Baron retrieves the blue-purple soul in one graceful gesture.

“Wait—!”

“Servant,” orders the Baron. Slim immediately straightens to their full height.

“yes m’lord.”

“Our acquisition needs further rest. I trust you will see to his safe retirement for additional magical replenishing?”

“as you wish m’lord,” Slim bows. Turning to Sans, Slim gently takes him by the shoulder.

“I-I’m _not_ just some _acquisition!_ ” Sans cries out, as Slim guides him out of the room, “I’m a monster! And I have a _name!_ ” If they were in a place with doors, Sans can imagine them slamming shut. Slim offers him a pleading look, but Sans is still too furious to back down. “How dare he speak to me that way!” he seethes, as Slim hoists him in their arms. “And stop coddling me, _please!_ ” Dark blue eyelights glower, smoking a black-blue as Slim pointedly pays his request no heed. Frustrated, Sans glares daggers at them before exhaling the anger away. “Slim,” he tries again, tone more controlled, “I can walk, I swear.” The phalanges grasping him clutch a touch tighter with a quake.

“i am afraid to say m’lord is right,” Slim finally replies. “you frightened both of us. i understand you wish to stand on your own, but we must continue as cautious vigils.” Sans crosses his arms impatiently. 

“You’re lucky you’re so accommodating,” he comments offhandedly, and Sans is oddly comforted by them. Slim holds him close like one would cherish a small child: warmly, gently firm. Despite this tendency, it feels nice being enveloped by them. Like Sans can be assured he’s safe with them.

Sans starts to recognize the rocks around them when Slim carefully sets him down. They nod to him expectantly, and Sans grabs onto the surrounding walls to steadily reach a place to sit. This is the place he woke up in, after that stint with the Baron. There’s a large, stacked slab-like formation (something between a flowstone and an exceedingly large cave raft, maybe?) in a convenient shape he can pretend is a bed, as well as smaller stalagmites the size of end tables littered about. Those ones hold his still-drying accessories, and from the look of it, they’re all, much to Sans’ disappointment, unfortunately damp. 

Sans splashes to the larger formation, while Slim’s sockets hone on him, both bats on high alert. It’s only when Sans is fully seated that the magic radiating around him settles.

He takes a deep breath and sighs, hanging his head.

“...hate that I still can’t walk properly,” Sans mutters.

“it is...an unfortunate symptom,” Slim agrees, as they glide inside. “but you have made much progress, considering but a few hours have passed,” they smile optimistically. Sans scoffs.

“Any idea on when I’ll have enough magic to?”

“ah...it is not in my knowledge,” Slim admits, “but i do understand procedures such as this require upwards of a fortnight to completely rejuvenate one’s magic.” Anger sparks in Sans.

“I can’t stay here for two weeks,” he protests, punctuating his words for emphasis. “I have a life to live! Everyone will be more than worried by then! What’s stopping me from up and leaving this Stars-forsaken cave?”

“i—“ Slim stammers, “n-nothing truly,” they confess, “but i would imagine it difficult to venture far without a majority of your soul, yes?” They say it so matter-of-factly Sans rolls his eyes in frustration. If it were someone else he’d all but hear the sarcasm lacing the statement. But Slim is right. 

“Sorry, I—,” Sans apologizes with an exhale. “All this is just...too much to handle all at once. I swear everything’s just getting _worse_.”

“it is only until you are strong enough,” Slim utters. “he will restore it to you.” With a hopeful smile, “i promise.” Sans is so tired of waiting. He’s so tired of ‘resting’ and sleeping.

“If I’m gonna be here for a while,” Sans sighs tiredly, “can’t you at least call me by my name rather than talk down to me like I’m some prize?”

“do you grant me permission to?” 

The strange glint in Slim’s socket makes Sans glance back at them. Making deals again? Making deals got him here in the first place. Rethinking his request, Sans puts a hand to his temple.

“I...I’m not sure.” Slim sits near him, and puts a gentle hand on his shoulder.

“to protect you,” they utter, “it is best if you do not share your true name.”

“But you shared _your_ name with me,” Sans protests. “Why can’t I share mine?” Slim stares at the wall in thought.

“in our time, giving your name, your _true name,_ to another is the ultimate form of trust. i did not offer you my true name, but a moniker. i...seem to have lost mine when i became what i am now,” they add sheepishly.

“O-oh.” Sans frowns, suddenly feeling quite nervous. “I’m—I’m sorry.”

“there is no need to apologize for the past,” Slim smiles. “names are, in their own form, power,” they explain. “to allow another the knowledge of your name is granting them access to a piece of one’s self. one’s _power._ much like the cumulation of your magic.”

“So...just as important as the Baron borrowing my soul?”

“yes,” Slim nods, “as this exchange is different from what occurred with my own, m’lord can restore your soul as easily as he took from it.” 

“He just...can’t because I’m not strong enough?” Saying the notion aloud seems to help in Sans’ understanding of it.

“the vessel in which the soul was taken from must survive in order for m’lord to return to the surface,” Slim recites. “to return your soul too early may result in your body rejecting it. and,” Slim gingerly drags a phalange down Sans’ mandible, “it would be unjustly wasteful to let you dust when you have the potential to live on.” Sans can’t hide his blush fast enough. Jerking away, Sans covers his face.

“I—uh...” Stars, his soul’s beat is loud to him. “Didn’t think of it like that.” Slim’s hand covers their teeth, in a bemused grin.

“do i have your permission to refer to you as ‘pet’?” Sans blinks, a wave of confusion furrowing his brow ridge.

“ _Wh—_ ” Slim is smiling shyly when he dares to look. 

“i—if you wish to not be labeled as our acquisition, may i call you otherwise?” they clarify.

“Like what?” Sans demands. “I’m not some _animal_.” Slim puts a phalange to their teeth in thought.

“do you prefer…‘blue’ instead?” It doesn’t sound bad, albeit a plain descriptor. It’s a little _too_ simple for Sans’ taste, but it’s better than answering to ‘acquisition.’

“Umm…sure? Yeah, you can call me Blue.” The growing smile that slowly creeps in Slim’s teeth makes Sans’ soul beat louder in his skull.

“then ‘blue’ you shall be,” they proclaim, and Sans swears he feels an air of unexplained joy around them. He blinks, unsure of how to respond.

”Okay,” Sans smiles lightly in return. Slim’s gaze lingers on him a while until they break eye contact. It feels a little melancholic around them now. Both bats stir, actively curious, as Slim rises. “Um…” Sans coughs, “are you heading out now?” They stop and reach into their cloak, retrieving a new length of fabric. Another blanket.

“my lord is in need of me,” Slim explains quietly, as they turn and offer it to him. “be at ease,” they assure Sans with a subdued smile, “for i shall return.” Sans envelops himself in the blanket tightly, feeling their residual warmth engulf him.

“O-okay.” Slim nods to him.

“should you require me, your small companions shall assist you.” Sans eyes them as both bats look straight at him almost on cue. The one on his front unhooks itself and flaps upward to roost above him.

“I’ll see you,” Sans waves dumbly, as Slim exits the chamber. The bat on his shoulder stares up at him, nuzzling its head before returning to a passive state.

Exhaling sharply, Sans runs a hand down his sternum. Swallowing, he looks down at it, a shiver ascending his spine. 

Blue, huh? Blue like his soul is supposed to be. 

In all senses of the word, Sans is scared of what he will find. Most of his soul’s with the Baron now, and seeing it so resplendent and healthy leaves Sans uneasy about the state of what’s left.

Gently, he summons the cumulation of his being. The glow is already wrong, much too dark for a normal soul. Giving out just enough light to not be a void. Gritting his teeth nervously, Sans examines it, tears welling at his sockets.

His current soul is in a state between dark blue and gradual shades of black from the center out. Until he’s fully recovered, Sans isn’t sure when he’ll be able to summon even the smallest construct. No wonder he’s having trouble with uprightness. No wonder Slim’s been carrying him around. His very being has weakened to the point Sans is amazed he hasn’t begun dusting.

Lesser monsters have dusted over more minor conditions.

Sans isn’t sure whether to consider himself lucky at this point. He just, doesn’t want to think of anything.

Hugging the blanket closer, Sans allows the tears to roll freely down his face.

—

Slim glides back to their master, tentatively brushing at the warmth against their chest.

Ah their poor pet…

They make sure their bats comfort him to the best of their ability. Only when they feel him settle, does Slim relax.

Minutes later, they find their Lord pondering the soul in his open palm. The furrow in his brow suggests concentration, a careful thoughtfulness.

The soul floats delicately, humming ever so slightly with the blue magic of their ac—their... _pet_. Purple eyelights flit briefly to acknowledge Slim’s presence before returning to the soul above his palm.

“He is distraught,” The Baron observes. 

“indeed,” Slim nods. “give him time, m’lord,” they suggest, “it is all we are granted, after all.” The Baron shuts his sockets momentarily, and closes his hand over the soul, gently guiding it back into his sternum. 

“When they said it was what needed to be done,” he says, as motes of blue and purple waver in the air before disappearing, “I did not think it would become this...involved,” he sighs.

“it was the one method of confidence available to us,” Slim assures him, “and we cannot be ones to ignore a gift from the heavens should they arrive.”

“It has been so long...” The Baron gazes at the ground before straightening his back. “Tell me what you have learned of this new world.” Slim reviews the differences in their head before listing them to their master.

“it appears we are not the only ones to have been imprisoned, m’lord. monsters of this era also witnessed their sealing underground as we, though under a different spell, as well as a different time.” The Baron nods, distracted.

“What else?”

“i suspect humans and their mages to be the culprits in their case. and it is only recently that the monsters were allowed their freedom.”

“I see,” The Baron mutters. “A gift indeed, he has become.” He paces about the room, tail swishing and flitting about. “And what of our acquisition?”

“he is a strong, driven sort,” Slim recalls. “he has shown much promise in the capabilities i have witnessed.” They turn, reminiscently smiling. “he reminds me much of our gallant acquaintance,” they add.

“I see,” The Baron paces, “Then we are quite fortunate it was him and not another.” He halts, a hand brushing at his shoulder. “There is still one seal he has yet to break.”

“m’lord?”

“My power, my _full_ power is still locked away,” the Baron demonstrates by summoning a flame, and only achieved a floating ball of fire smaller than his palm. When he attempts to use it to burn a rock, it fizzles away mid-throw. “Currently I am of no real use until he can disrupt the spell’s flow,” he huffs in annoyance. Slim’s brow ridges furrow in objection.

“we cannot keep using him this way,” Slim protests, “he lacks the strength needed! he has not fully recovered from his initial draining and will perhaps even _dust_ before you are fully freed, m’lord!” A sob courses through them. “helplessness _plagues me_ , m’lord! how am i to serve you appropriately if i am barred from it?”

“You do more than enough for me, Servant,” The Baron smiles assuredly, brushing their mandible with a clawed hand. As Slim nuzzles into it briefly, the Baron’s other hand traces down before taking hold of Slim’s cowl, and discreetly under it, their metal collar. “It is about time I do the same for you.” His purple eyelights smoke with a heat Slim is all too familiar with, and Slim’s breath catches in their false throat.

“h-here?” they stammer, as he releases them, “at this moment?”

“Come now, Servant,” The Baron teases, slowly undoing his ascot and unbuttoning his waistcoat. “You are more than welcome to feed.” Revealing the bones of his clavicle almost makes Slim’s knees buckle. Inviting them forward with a finger, their Lord smirks. “Have we not waited long enough?”

“o-of course, m’lord,” Slim breathes, watching their master with a reignited hunger.

Slim can’t remember the last time they’ve felt so thirsty.

They’re in a daze as their Lord has their rapt attention, tantalizingly exposing his shoulders. A shiver surges through their entire body.

“That’s it~” the Baron encourages melodiously, as Slim stumbles forward into his arms. “Don’t keep me waiting,” he whispers heatedly into their temple.

The gold of Slim’s fangs brush against the bone as they part their teeth to feed.

It’s like the floodgates have opened and angels chorus the moment Slim sinks their fangs into the glorious marrow of their Lord.

They never want to starve ever again.

They never wanted anything more than this.

Drink they do, gold unleashing the deep purple marrow from the confines of mere bone.

Their Lord’s cries are music to Slim’s acoustic meatuses. When their teeth find another area to bite, the Baron squirms under their ever-tightening grip.

“Ah~ I... _missed_ this,” he gasps. With a lascivious growl, “Feed to your soul’s content, Servant.” 

The amber of their eyelights wildly igniting gold, Slim finds they can’t obey fast enough.


	7. Chapter 7

**Summary for the Chapter:**

> Let's have a little confused-but-riding-it-out-secondhand-sex shall we? ;)

**Notes for the Chapter:**

> It's been very busy, what with working full-time again and having little time/motivation to write, but I was recently inspired to pick this chapter back up, and I'm very sorry for keeping you all waiting as long as I have. 
> 
> You've been a very patient audience.

Sans can’t sleep. It’s not from the dampness of the stale air, or because he’s cold. It’s the Stars-damned rock he’s laying on. Sans curls into his coat, trying to use its surface area as cushioning, but almost to no avail. Almost—being the operative word. His coat wasn’t meant to be used as a makeshift bedspread, and though his feet are shivering his socks still need to fully dry before he can entertain the notion of wearing them. What he’d give for a blow dryer about now. What he’d give to be at home.

There’s no helping it though. Even if he sorely wants to try and find a different way out, he hasn’t the energy nor the stability to go any further than outside the room. Plus, if he wants to be safe, he’ll need Slim to come. And for optimal safety, that means bringing along the Baron too. Sans groans at the thought. The bat on his shoulder peers at him. Sans shakes his head.

“‘m fine little fella,” he waves a dismissive hand at it. “Just thinking about stuff.” The bat cocks its head before nestling back in the crook of his neck. The way it curls into his shoulder is very endearing, but Sans offhandedly wonders why it doesn’t join its friend above him. 

Sans tries not to think too hard about it.

Rolling to his side unoccupied by the bat, Sans sighs. It wouldn’t be a bad idea to try and explore the cave more; given how some parts of it are definitely unnatural. Maybe it could lead them to some hidden passageways, or link to the Human settlement. There isn’t much keeping the three monsters to these what, two or three select caverns, nor is it safe to stay in a place where there’s literally no food. Skeletons don’t need to eat per say, but it doesn’t mean Sans doesn’t crave consumables. Back in the Underground, monsters were fortunate to some degree to have a place like the Dump to scavenge from, though they did eventually also create their own food with whatever they could forage and magick themselves. 

Sans’ thoughts wander to the possibility of magic in this cave besides what holds the Baron and Slim here. He’s learned a little survival training from Alphys, but he doubts there’s enough magic in him to conjure anything meaningful. Even if he could, Sans has no idea what the Baron even eats. Would he think it abhorrent of Sans if he were to conjure him up a cinnamon bun? If Sans offered him rations, would the Baron think them revolting? What would his courtly demon tongue think of the drastically different cuisine of the modern monster? Sans has little to go on besides the Baron taking a good portion of his soul, though he’s certain if the Baron also needed a soul to live, he most likely wouldn’t eat it. Be _sides_ , the Baron has sharp teeth, and if Sans knows anything about those, teeth like that are meant for meat, meant to rip. Meant to…

Before he can finish the thought, it’s like Slim’s golden fangs are grazing his cervical vertebrae again.

...Bite.

Sans has trouble shooing away the thought now that it’s formed. They’re teeth to leave marks with. Much like Slim’s, only more ravenous. Much like fangs only they’re pointed everywhere. The kind to gnaw bones with. Sans flushes as the thoughts seem to wash through him. 

_The Baron, purple eyelights in a deep glow, catching him in an inescapable embrace, claws raking at his back—Slim, their gorgeous eyelights staring down menacingly, intimidatingly down at Sans. Both of them have teeth quite sharp, jaws quite powerful. They could easily take him if they both wanted to. They could easily overpower him should they choose to together._ Sans involuntarily shudders, and stops his hand from descending further than his ribcage. He’s getting much too excited, and at the most inappropriate of times. 

He could be taking off right now, wringing the water out of his socks, and putting on his boots to brave the tunnels again. He could extract himself from the gaze of the smallest, flying watchdogs and scout ahead to find a path to the Surface again. He could be doing anything, but here he is, fantasizing about getting bitten by two ancient, yet handsome monsters. Sans sighs, mildly exasperated. He feels a lot like the female protagonist in one of those trashy, graphic romance novels Undyne likes to read sometimes. (" _Obviously_ it's a piece of ancient Human literature targeted toward a female demographic Sans," she said once, "and it's very taxing material to study. You wouldn't understand.") ...Undyne obviously missed that Sans has a perfectly good taste in literature, thank you very much. Still, bringing that comparison up is not a good thing, but he doesn’t know how else to think of it. Stars, what’s even happening to him? Sans is certain there’s something igniting this desire in him, but it’s much too strong to simply ignore. Though, oddly enough, it’s not so much to negatively affect his poor soul. Frowning, Sans allows a whine to whistle through his teeth. Well, if he can’t stop it, he might as well ride through it. Though, if there ever was a more embarrassingly unsexy place to jack off, it's in a dank cave with no other sorts of stimulation besides what was bombarding Sans. Well, it could be worse. Something could always interrupt. 

Considering what he speculates the Baron and Slim to be doing though, Sans presumes they’ll be just as occupied as him. Tentatively, Sans reaches down to gently brush at his spine. His hand travels down quicker than he expects, and his phalanges ghost over his iliac crests, dipping into his pelvis.

Sans shivers. He needs this. 

The magic is forming, coalescing at each gentle stroke. It’s when it’s nearly formed Sans feels the first phantom bite. Gasping, he cries out, nearly knocked back by the unexpectedness. A gentle suck, the folds of a tongue— Sans can almost imagine Slim’s eyelights guiding him down into the feeling, their weight on top of him, as his bones quiver in anticipation for the next bite.

—

_The Baron gasps and moans as his Servant’s fangs clamp down on his bones. Their tongue laps up the marrow that has sprung from the injury. It’s a warm, numbing caress._

_“More,” he breathes. “_ **_More._ ** _”_

_Their eyelights gleam a predatory gold, as they drink of his marrow like they used to. They’re regarding him with a sharp gaze, overbright and hungry—_

_They don’t need to speak for the Baron to know their answer._

—

The more he thinks about Slim’s eyelights, the easier it is to relax into the sensations demanding his attention. His magic trembles as it molds itself into something he can externally stimulate and grab. Sans has never felt this eager to wank before. He’s never felt like he needed to so desperately. His back arches, his soul sings as his chest is awash with the black-blue light of his exposed soul. Sans groans unabashedly.

He’s only counted a few bites, but it feels like fangs can pierce him everywhere, in every available bone. Sans is so sensitive, it’s like his entire being is singing. The delicious sink of sharpened teeth penetrate into his limbs, vertebrae, anywhere they can reach—Stars, is he _loving it_.

  
He can imagine Slim’s gaze locking into his, forcing Sans to stare, to fall deeper into their spell. Sans kicks around like there’s someone on top of him, but he’s otherwise pinned to the spot. Sans writhes but he’s trapped. Tied up again, this time in a different sort of way. The sudden hot breath at his neck makes a shiver rush through his cervical vertebrae, his spine. He can barely hear the indistinguishable pants and whispers of someone who wants more, who’ll _give_ more. Sans moans in compliance as he basks in the lust that has overcome him.

“Please…” he begs to no one in particular, furiously masturbating as fast as he can, conjuring swirls of glowing amber in his head for his eyelights to follow, “ _please—_ ”

—

Slim has always been the pinnacle of control, the master of their desires, but oh do they throw most of it away now that they’re with their lord again. Now that they are granted the permission to drink to their fill, they almost can’t hold back their joy—having their lord again, his bones under their teeth, his body under their frame, his moans ringing through their skull—it’s like a dream come true. It’s more than Slim realizes they wanted. It’s so much they can also see the blue of their lord’s borrowed soul glinting alongside the purple glow of the Baron’s. 

They can only imagine their pet equally enjoying the ministrations. Slim surges into action with more fervor at the thought of Blue engulfed in pleasure too.

They want to feel his marrow on their tongue, bask in the glow of his radiant blue soul—watch as his dark blue eyelights roll back and _accept Slim as his—_

A howl beneath them, a cry for more.

Slim dives in again in a flurry of flushed bone.

—

He can’t _take it_. The phantasmagorical weight of a hand on his sternum leaves Sans breathless. He enjoys it too much to writhe away. His hand is slick from his own fluids, pumping up and down so fervently he’s sure he’s left a raw spot. The phantom hands are grabbing at his shoulders, gripping at his sternum, phalanges curling between his ribs with animalistic vigor the thought of them ripping out his sternum to expose his soul crosses his mind.

He’s so hot and bothered right now. He needs to keep going. _Has_ to keep going. Part of him isn’t scared anymore, of losing himself, of falling prey to old monsters.

He just wants. And Sans will do whatever he can to get it.

—

_Purple magic has quivered into the shapely form of ectoflesh, concentrated to his pelvis. The Baron’s folds shudder as he bucks his hips, wanton and eager. He needs this. He_ **_wants_ ** _this._

_It has been too long._

_Teeth retreat long enough to grant him a moment of reprieve as his Servant licks the marrow from their fangs deliciously._

_“m’lord,” they breathe, “what do you wish of me?” The Baron grins salaciously._

_“If you are to use your tongue,” he replies, grabbing his Servant’s skull so they look up at him, “I require it elsewhere.” He can feel their form shudder at the command. “Make me sing, Servant.”_

_“as you wish,” his Servant can only gasp._

—

Sans stiffens, before relaxing to welcome the licking sensation at his nethers. Everything about this feels so good. 

Everything about this is just so... _hot_. Sans has never considered himself depraved before, let alone kinky, but all of these new experiences are opening up a new world to him. Stars— Sans keens, whimpering aloud. The licking is a constant speed, just enough to tease, not enough to get off on. He just needs a little more—

The licking stops.

Sans whines loudly, desperately. But then something takes its place.

Oh. Sans’ eyelights roll up. _Oh..._

He didn’t conjure a cunt, but now Sans wishes he did. His ectoflesh seems to eagerly accommodate the phantom intrusion all the same. Sans is almost surprised he’s not literally dripping everywhere.

_He can imagine being commanded to lick it up. To clean his mess. Like the slut he is._

Damn would Sans be the best slut—

He moans, feeling the head slowly inserting itself carefully in. Sans isn’t too keen on anal in particular, but he’s played around with his parts before, dabbling in customizing for the appropriate occasion. It’s only now he realizes the appeal of having both conjured at once. The best of both worlds, really. Maybe if he just—

It’s a minor distraction, being penetrated, but Sans concentrates enough and he sighs contentedly as he receives the full length. Sans is so full. He had no idea it’d feel this good to be.

Stars would he give to have someone to kiss...to have someone tangible to reciprocate with. To thank with his tongue and teeth. Sans humps the air as he continues masturbating, back arching, trying to will himself to the phantom body over him. Willing them into existence.

Willing them to him.

Sans cries out in bliss when he feels the brush of fangs against his cervical vertebrae.

“S-Slim—!” He moans, “Oh _Stars—_ ” He needs them. Oh he wants them so bad— Desperately close, Sans gasps, sockets tightly shut in concentration before he allows the word he’s been repeating in his head to escape. “M-Master…!”

—

Slim’s eyelights flash brighter than they’ve ever been. Something has changed. Something…

They looked down at their Lord, their splendiferous Master.

“Servant—” he smiles, lovingly, adoringly.

_“M-Master…!”_ Slim sees their pet in their Lord’s place, blue eyelights hazy and large, expression desperate and pleading. Slim freezes, equal parts shocked and aroused. The bats…

He accepted it.

Slim can faintly hear his cries in his skull, their pet’s ministrations, the howl of his release.

_He wants them._ **_Needs_ ** _them._

**_Desires them._ **

Slim’s teeth part, amazed. Their Lord interrupts their thoughts with an excitedly open kiss. Slim returns it fervently, tongues exchanging fluid. Their sharp teeth rake against their Lord’s as Slim allows him to push them down, so they’re under him, so they can submit to him like they always do. Their Lord’s teeth pepper the bones of their neck, and Slim groans, tongue latching into whatever protuberance they can reach, reciprocating his attentiveness.

“Servant—” he groans, grabbing for their collar, guiding their neck so they can gaze into the deep purple of his eyelights.

“m’lord,” Slim pants heatedly, steadily driving into him, still maintaining a rhythm.

“Kiss me,” their Lord commands, and Slim’s teeth clank obediently into his. Their fangs travel from his teeth to his zygomatic processes, down his mandible, before gently sucking on his cervical vertebrae. The Baron moans, shifting closer so Slim may drink of him again. His teeth brush against Slim’s skull once more. “ _Drink,_ ” he encourages. “I have waited too long to enjoy you, my Servant.” Slim’s skull grows foggy with their Lord’s coaxing. Blindly, they crane their neck to angle their fangs into him once again. “Such a good Servant,” their master praises, as Slim’s fangs prick into his bones once more. His initial purr grows to a rumble, soon rising to guttural grunts as Slim pistons inside him. “ _Servant…”_ They thrust deeper, quicker. Slim grabs their Lord and rolls to reposition them so he is under them again. “ _S-Servant…!”_ His claws catch on their back, phalanges piercing into the fabric to grasp them by the ribs. Slim’s pace accelerates, fangs clamping down onto the nearest bone to _drain from._

Their Lord’s cries have become a state between quiet moans to a gasp. The air around them both has heated significantly, magic hanging like a fog, accentuating the arousal of both master and servant. His dual-colored soul gleams through his ribcage, Slim has to bite down the urge to imbibe in it too. “I’m so close,” he whimpers. Slim obliges by nibbling on his cervical vertebrae, kissing hungrily into his jaw, his burning hot face.

“ _cum for me my lord,_ ” they whisper. It’s not a command, nor an acquiescence. He wants this just as much as they. Slim thrusts into him, both hands at his wrists, holding him down. Watching him writhe so desperately, their willing prey. Their hooded sockets smolder hungrily down at him, pristine gold eyelights igniting. _"cum for me,”_ they rumble, their ribs literally vibrating. _“cum.”_

It’s just enough to push him over the edge. 

Their Lord cries out as he clenches, fluids finally spurting from him, both from his soul and from between his legs, before he collapses into Slim’s arms. He’s gasping, but he clutches so tightly at them, Slim waits until their Lord rolls over to offer him an embrace.


End file.
